I've been playing D&D since the first player's guide came out in the 70s. The game has changed a lot, but honestly the rules regarding scrolls should have been hammered out and clearly stated long before now. The fact that we're still debating what they mean is not a positive for the writers. 

For example:  https://www.dndbeyond.com/sources/dnd/br-2024/magic-items#Scrolls  says "Any creature that can understand a written language can read a scroll and attempt to activate it unless its description notes otherwise."  Pretty broad!   But at the same time: https://www.dndbeyond.com/magic-items/9229085-spell-scroll  quote "If the spell is on your spell list, you can read the scroll and cast its spell without Material components. Otherwise, the scroll is unintelligible."  That seems like a complete contradiction?

Obvious caveat: every dm runs their game however they please and can change any rule they like.

In the old days you needed a "read magic" spell to read a scroll or spellbook. Once read you knew the scroll and could use it. But only wizardly types had that if I remember right.  Clerics and druids didn't.  <shrug?>

Personally I like restricting spell types to certain character classes.  If everyone can cast any scroll, you lose specialization and individuality for the classes.  If you happen to score a ton of cleric scrolls, you don't really need a cleric in your party.

Action Surge is only for your turn, plus you could instead take 18 levels for 3 attacks and Bladesong, for an ac, speed, etc. bonus for 6 attacks, 9 only once *and* this is possible in the game if you succeed the check.

Is it possible to read a spell scroll that is not from a warlock spell list with the eyes of the rune keeper?
The description for a spell scroll says: "A Spell Scroll bears the words of a single spell, written in a mystical cipher. If the spell is on your spell list, you can read the scroll and cast its spell without Material components. Otherwise, the scroll is unintelligible."

However, Eyes of the Rune Keeper says "You can read all writing".

So, does that mean a warlock with that invocation could read any spell scroll, despite that spell not being in their spell list? Or because the writing is in a mystical cipher, it prevents the invocation to work?

Quote from DakTheWizard >>

I've been playing D&D since the first player's guide came out in the 70s. The game has changed a lot, but honestly the rules regarding scrolls should have been hammered out and clearly stated long before now. The fact that we're still debating what they mean is not a positive for the writers. 

For example:  https://www.dndbeyond.com/sources/dnd/br-2024/magic-items#Scrolls  says "Any creature that can understand a written language can read a scroll and attempt to activate it unless its description notes otherwise."  Pretty broad!   But at the same time: https://www.dndbeyond.com/magic-items/9229085-spell-scroll  quote "If the spell is on your spell list, you can read the scroll and cast its spell without Material components. Otherwise, the scroll is unintelligible."  That seems like a complete contradiction?

Obvious caveat: every dm runs their game however they please and can change any rule they like.

In the old days you needed a "read magic" spell to read a scroll or spellbook. Once read you knew the scroll and could use it. But only wizardly types had that if I remember right.  Clerics and druids didn't.  <shrug?>

Personally I like restricting spell types to certain character classes.  If everyone can cast any scroll, you lose specialization and individuality for the classes.  If you happen to score a ton of cleric scrolls, you don't really need a cleric in your party.

 someone brought it up earlier and had to double check too, but its bc not all scrolls are spell scrolls. Example being Scroll of Protection (https://www.dndbeyond.com/magic-items/9229016-scroll-of-protection), a scroll that everyone can read bc its not a spell scroll and doesnt have that "unless described as otherwise" i was like wait what and then saw that and was like ooooh bc yeah it should be like you said if on your spell list than should be bc then why have a spell list tied to you and your class/subclass

What is the $ amot

The time and price for crafting Spell Scrolls are in the Equipment section of the D&D Beyond basic rules. Here's a link:

https://www.dndbeyond.com/sources/dnd/br-2024/equipment#ScribingSpellScrolls

From the 2024 PHB:

Magic Initiate: Level 1 Spell. Choose a level 1 spell from the same list you selected for this feat’s cantrips. You always have that spell prepared. You can cast it once without a spell slot, and you regain the ability to cast it in that way when you finish a Long Rest. You can also cast the spell using any spell slots you have.

Prerequisites for the Scribe: To scribe a scroll, you must have proficiency in the Arcana skill or with Calligrapher’s Supplies and have the spell prepared on each day of the inscription. You must also have at hand any Material components required by the spell; if the spell consumes its Material components, they are consumed only when you complete the scroll. The scroll’s spell uses your spell save DC and spell attack bonus.

Spell Scroll: A Spell Scroll bears the words of a single spell, written in a mystical cipher. If the spell is on your spell list, you can read the scroll and cast its spell without Material components. Otherwise, the scroll is unintelligible.

Thus, a character with the magic initiate feat (and proficiency in Arcana or Calligrapher's tools) can scribe spell scrolls but cannot use them unless that spell is also on their class list. So a level 1 fighter with the shield spell from magic initiate can scribe shield spell scrolls but can't use them themselves.

There's a difference between a magic scroll and a spell scroll. The working you linked in the second part is specifically for a magic scroll. Magic scrolls don't have to cast a spell specifically. A spell scroll is a scroll that casts a specific spell.

I think there are two ways to interpret how Eyes of the Rune Keeper would work.

It says you can read the writing AND cast its spell, so with Eyes of the Rune Keeper, you could read the scroll, but not necessarily cast the spell. The magic itself is the mystical cipher

Or, it's like Thieves Cant, where it's written in code so even though you know what the words say, it has a hidden meaning.

Personally, i'd lean towards the first option. Let your warlocks read it. They could already read it if you cast identify, so let them read it but don't add any additional context behind the name. Now you can have cursed spell scrolls. I would even go so far as to let them cast the spell like Thief Rogues can where they have to do an arcana check but the DC is 20+the spell's level, but they get to add their warlock level to the check as well. They will probably be lower intelligence, so they will have a hard time on even simple spells until they get up in levels.

Rules as Written, you still can't cast the spell.