BUG - Custom Backgrounds with 2014 Legacy Spells: not able to add spell to spellbook (was also true for items)

Campaign ongoing since 2023, all Legacy.

I made a custom background, adding Water Walk (Legacy 2014 version) to the Sage "Additional Spell List" section, because I accidentally let my Wizard player copy it into his book (not remembering that Water Walk was not a wizard spell).  When we swapped the background to his sheet, and added it to his spellbook via LEARN, the 2024 version of the spell is what appeared. This was a month or two ago.  

Now, we can't add the spell at all...
- Just to verify that I had added the correct spell, I just went and edited the background, deleting the additional spell list, and recreating it, to ensure the 2014 version of the spell is what is on there.  Removed and re-added the background it to his sheet.  Now, the 2024 version is still the description that appears in the "Add Spells" list, but when we click LEARN, it goes to an "Unavailable Content" error page. 
- Added both the 2014 and 2024 spells to the background, and just the 2024 version shows up (in the Add Spells list), and gives the same error page when trying to add it.  Happens when trying to add from the Character sheet, and the Character Builder.
- Went back and gave the background ONLY the 2024 version, and now we can add it back to the character's spell list.  But, it is the 2024 version.
(I guess this means it is possible I had the 2024 spell in the background initially, though I don't believe I did.  Regardless, the problem still exists as detailed above, making it impossible to include a 2014 spell in a custom background.)

This also happened with a custom item I had made, granting the wielder Chill Touch.  Mousing over the spell on the item page showed 2014, but the PC was granted 2024.  Remaking the item with the 2014 spell (again), and re-equipping the item, seems to have fixed the issue for now.  But it definitely had the 2014 spell in the description, and had given the PC the 2024 version of the spell.

Screenshot showing the item was originally made with the 2014 version of the spell, taken after we realized (during game) the PC's sheet was showing the 2024 version:

The tooltip you've added to the description is totally separate from the spells you can add in the section below. 

Tooltips for spells will use the 2014/5e version if you use the "spell" tag and the 2024/5.5e version if you use the "spells" tag. This is purely based on which tag you use and isn't connected to anything else about the item.

The two versions of the spell are implemented as separate spells in D&D Beyond, so you have to make sure you select the right one from the list when adding it via the "Spells" section.