Description
Modems broken by Create contraptions. Modems break by being turned into the entity / block state from the Create mod contraptions.

This issue has been reported and experience by a lot of other players. See thoses posts :

Creators-of-Create/Create#4959
cc-tweaked/CC-Tweaked#948

To Reproduce

1. Make a contraption with modem glued to it.
2. Move or turn the contraption so that it becomes an entity.
3. Turn the contraption back into blocks.

Result : Modems broke

Expected behavior
Modems not breaking off contraptions.

To resolve issue
Ok, so I have a pretty clear idea on why this is happening. Create uses the block tag "create:brittle" to indicate to it's contraption that objects such as redstone links or Valve handle should be placed last when the contraption converts back into blocks. That way blocks with the "create:brittle" have something to attach to.

Since CC:T modems (ender or wireless) don't have that "create:brittle" tag but also need to be attached to a solid block, I believe the contraption tries to place them first, therefore making them insta break / pop.

Adding this tag to modems may fix the issue. Since CCC:Bridge adds compatibility between Create and CC:T, I thought it would be a good idea to report it here.

Hope you can help,
MintTee

Software :

• Minecraft Version 1.20.1
• Mod Version v1.6.2b
• ModLoader Fabric

Create:safe_nbt seems to tell create that the block can have its nbt saved in a schematic without duplicating items, so not related as far as I can tell.
https://github.com/Plite7067/CreateCCModemFix I made this datapack which seems to solve the problem by adding the brittle tag as the original poster suggested. It should work for all versions necessary - I have tested that it applies the tag correctly on 1.18.2+

Thanks for the acknowledgment.

There is also this "create:safe_nbt" block tag which I guess tells the contraption to keep the nbt data of the blocks in order to place them with the same state. Not 100% sure though.

Hey, thank you for this issue!
This sounds like a great idea, I didn't know about that actually.
I will look into this.

I found a workaround to this issue.

It's possible to use turtles on contraptions. Since they are considered a solid block, they dont need a support block (they can float mid air). Therefore, unlike modems, they wont break when turned into a contraption form or back into the block form. They will, however, shutdown and restart.

If you create a program called "startup" in the default directory and have the "shell.run("program_name")" inside it, it is possible to run any program automatically as soon as a computer / turtle restarts.

Maybe this temporary workaround can help a few people experimenting with Computer Craft on Create contraptions.