Using Davincis Vessels version: davincisvessels-1.12-6.340-full
Minecraft version: 1.12.2
Forge version: 14.23.5.2854
No crash log to post

Using Davincis Vessels with Immersive Engineering.

I placed a few Davincis Vessels blocks onto my airship, assembled and mounted the ship. However when trying to disassemble, IE blocks detached separately from my ship, which did not disassemble and just kicked me out in a parachute. The IE blocks were still on my ship, and were duplicated into the world every time I tried to disassemble.

Happy to share any more information that will help you fix the issue, just let me know.

Wow. I've got the same problem, only most of my blocks are vanilla except for lanterns from Charm. I was near block limit for my airship though, so there's a possibility that that could contribute to it. I'm playing on version 1.12.2, MC Eternal Modpack, Twin Peaks Gaming server. screenshots of problem attached.

Okay, so I've figured out a bit of a workaround. When making a ship/airship/submersible, use ONLY vanilla blocks and blocks provided by this mod, and try to keep the number of blocks used under 2k. After adhering to these two things, I haven't had a problem since.
So in essence, don't use modded blocks until configurations or the mod is updated to include them, or freaky stuff like this happens.

same problem , this makes me delete my world many times cause i cant delete the ship

SEEE

If you have the Problem that you cant delete the ship you can kill it with kill @e (WARNING: if you are not familiar with this command, It kills EVERY entity that is currently loaded so be cautious) (you can probably figure out how to kill ONLY the ship but i didnt xD)

Thats how i dealt with the ships which duplicated