I’m running a campaign and at least two of my players have had, in the past month or so, random “always prepared” spells and/or cantrips appear on their character sheets. Searching the compendium results in nothing, and only a Google search brings them up as some home brew content.

Specifically a level 4 Aasimar cleric had “medic’s mark” and “Snowball” (just snowball) appear, while the human pally had “Blazing vengeance” appear.

Any reason this could be happening? Both sheets have homebrew turned off.

Spells & Feats #1: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq)

To clarify - I did not make these spells. These are appearing randomly even though we have turned homebrew content off. This isn’t me asking why my homebrew spells aren’t acting correctly, this is me wondering why some other person’s homebrew spells are invading my player’s sheets.

The creator of that PC and, when that PC is in a DM's campaign, that campaign's DM can change anything about the PC. Nobody else has access to do anything to how a PC is set up. If you're the campaign's DM, then your player is doing something in homebrew, whether they realize it or not.

Now if this homebrew content is just showing up in manage spells / add spells, manage feats but not selected, manage inventory / add inventory, choose a subclass, or choose your race as available choices, then someone has added that homebrew but is not using it.

I'd suggest you turn the homebrew option off on the PC builder's 1st tab. Only turn it on when you as the DM want to add something homebrew to that particular character, then turn it back off.

Homebrew that has been added prior to the Homebrew switch being turned off is still on the PC, just no new homebrew stuff can be added.

That’s what I’m starting to figure out. It looks like he had homebrew turned on originally by accident and it’s an “always prepared” class spell, so it just applied to his sheet and now we can’t remove it. Exciting!

If it's always prepared that would lead me to think it's more than likely a homebrew subclass.

As the player of the Pally, Oath of Vengeance is, last I checked, a fairly standard subclass of Paladin...

What I have found interesting right now... I have 4 characters attached to campaigns. I never, ever, turn on homebrew content. All four characters have "Homebrew Content" randomly switched on. All characters not in a campaign are not switched on. 

Most PCs are created with Homebrew Content and M:tG content automatically switched on. I don’t know if that has anything to do with it or not. Your DMs might have switched it on. 🤷‍♂️ 

But spells sneak through even when it’s not on because they have a back door in because of how the class list for spells and the list of spells for subclasses are interlinked to sync up. And since all homebrew is automatically shared within campaigns, just hidden without that setting turned on, any spell someone made with a subclass attached sneaks through.

Someone in the campaign has created those homebrew spells, or added published homebrew spells to their homebrew collection, that apply to Cleric/Paladin subclasses. Unfortunately, this effectively edits those subclasses, whether wanted or not, even if the character has Homebrew Content disabled. You'll need to ask around your players to see who has those spells in their homebrew collection and get them to remove them.

Sposta and Naru are hitting the nail on the head - someone in the campaign has created homebrew cantrips and associated them directly to a cleric or paladin subclass. When levelled spells get associated in this way to Cleric/Paladin/Druid subclasses they get treated like domain spells (or Circle of the land spells for druid).

When someone associates a cantrip to say a cleric subclass, the system treats them like domain spells and puts it in as Always Prepared, however as we all know that doesn't make sense for Cantrips. And the sheet sits in this weird state with a delete/remove options (like a cantrip should have) but gets an error because of the logic gap between deleting something that is always prepared (I think even Spock would get a headache working through this).

The first step would be speaking with the group(s) your character(s) is/are in a campaign with and find out who has created these (or added them to their collection). Then getting them updated (or removed).

Any chance of the coding team fixing this bug?

Quote from Sorce >>

Sposta and Naru are hitting the nail on the head - someone in the campaign has created homebrew cantrips and associated them directly to a cleric or paladin subclass. When levelled spells get associated in this way to Cleric/Paladin/Druid subclasses they get treated like domain spells (or Circle of the land spells for druid).

When someone associates a cantrip to say a cleric subclass, the system treats them like domain spells and puts it in as Always Prepared, however as we all know that doesn't make sense for Cantrips. And the sheet sits in this weird state with a delete/remove options (like a cantrip should have) but gets an error because of the logic gap between deleting something that is always prepared (I think even Spock would get a headache working through this).

The first step would be speaking with the group(s) your character(s) is/are in a campaign with and find out who has created these (or added them to their collection). Then getting them updated (or removed).

 Okay, so this is confirmed that basically if anyone in the campaign has a homebrew spell that applies to a subclass in their homebrew collection, it forces it's way into anyone in the campaign who has that subclass as a class feature, no matter if we have homebrew turned off or not. Since a couple of our players do play other campaigns that have those homebrew features included, they can't just remove them from their collections without messing up the other campiagns. What are we supposed to do in this situation? Is there a fix to keep unintended homebrew out of our campaign or these spells from cluttering up our sheets/having to remember what's valid and what's not all the time?

So the other campaign(s) homebrewed the spells? Then your players don't need to have the spells in their own homebrew collections. So long as a single someone in the campaign where the spell is necessary has the spell in their collection, then it will apply to everyone in that campaign.

And/or, whoever created the homebrew spell could just remove the Cleric/Paladin subclasses from their spell, and it will still be available for use in general.

Alternatively, the DM or whomever decided to make those spells available could try a different homebrew method. I suggest you refer them to the Homebrew Forum for advice on how best to do so.