binding string ids to integer ids mess up

[TheBndgPanda]

Minecraft Version: {1.19.2}

Forge Version: {43.2.0}

Logs: {No crash}

Steps to Reproduce:

1. Have mods installed (affected mods in this case were: Carpet Trapdoors, Macaw's Paths, Macaw's Fences and Walls, Fantasy Furniture)
2. Install new mods (Mod in question was: MrCrayFish's Furniture Mod)
3. Be unlucky (The issue does not seem to be due to lacking compatibility, but seems to happen somewhat "at random"

Description of issue: Reposting the issue from another forum, including a response that seems to have identified the problem.

"So, I am unsure if this is the right place to even ask my question, as I don't think the issue has to do with FF itself. However since there are a lot of knowledgeable people here and since it might be an FF issue I will post my problem here.

I have a server running the mod. It worked fine for about a month now. However, yesterday I added the MrCrayFish's Furniture Mod and it seems to have messed up the block ID's. When I loaded the world, all the blocks of FF were replaced with other blocks (suddenly the Nordic Bookshelf was replaced with FF's bottles and bookpiles). FF is not the only mod that is affected (Namely, Macaw's Paths and Fences and Carpet Trapdoors are also affected). So I was wondering if anyone else has had compatibility issues with FF and MCF's Furniture Mod.
Additionally, if anyone has an idea how to resolve this issue, it'd be much welcomed. Even after uninstalling both FF and MCF, the world is full of glitched up blocks."

Response:
"this sounds like a forge or maybe vanilla issue as the backing integer ids are handled in forge/vanilla registries.
while modders register with a unique string id prefixed with the mod id to not conflict with other mods (:)
sounds like after installing the other mod, the trickery forge/vanilla does to bind the string ids to integer ids got messed up
while loading the world"

• "Is this also an issue that can occur when updating the mod versions?"
  "potentially yes, if a mod added/removed anything to/from the registries (any game elements, blocks, items, entities, block entities, menus etc) every element needs some integer id to be bound to while binding them there is a none 0% chance that it can fail usually a rare occurrence but it can happen, and unfortunately you got unlucky"

[rezonant]

To rule out some possibilities, can you check whether you get the incorrect (new) block item back when you break one of these blocks or the correct (old) block item?

[TheBndgPanda]

Both, kind of? When the block (or item, as I am mostly talking about furniture here) in question is replaced by items of the same mod it gives me back the original block. If I place that block it is once again replaced by the same "new" blocks. For blocks that are replaced by a different mod, I will get the new block back. Though it's also not a 100%, so it might also be random.

[TheBndgPanda]

After deleting the level.dat files and letting the server recreate them, without the MCF's Furniture Mod, at least the macaw's mods seem to be fixed. However, after placing the nordic bookshelf from the fantasy furniture mod, it still spawns a 2x2 of glass bottles instead. Now, if I right click these bottles my game crashes, with the following error:
The game crashed whilst rendering screen
Error: java.lang.RuntimeException: Slot 9 not in valid range - [0,9)

Maybe that helps in a way

[marchermans]

You should not be using the integer id's to store state!
Allthough they are saved, partially, it is kuch better to store the name!

[TheBndgPanda]

I am not a mod creator or anything of the sorts.