Merge blocks that cause all ships to stop moving.

So me and my friend have a multiplayer world (not dedicated and we do use mods from the steam workshop), we were planning to attach two large ships to a very big ship( all three are large grid), to do this we attached both the "large" ships to the "bigger" ship with merge blocks. Everything was fine until i got out into space ( no p-gravity) with the 3 ships attached with merge blocks and then my friend told me that a small grid ship still sat on our Earth-like base had stoped allowing him to interact, by this i mean the ship still had everything turned on. however it did not allow him to use the thrusters, so if he pressed W the thrusters would not "activate". mouse interactions would not work either like trying to steer the ship, gravity still interacted with the ship, however keybindings in the hot bar would work and the control panal in inventory would allow him to turn stuff on and off but still nothing would work. As for me this bug only happend after i closed the multiplayer world, but when i tried to restart the multiplayer world my game crashed. Once i loaded back in (still flying the 3 merged large grid ships) i had the same bug happen when no keyboared or mouse interactions would work the thrusters or let me steer it was like the ship was stuck in place, thrusters wouldnt even show an animation that they were at full force. I could get out of the ship and fly about as my character no problem, another thing is that when i tried to turn the power off with "Y" it only made the noise of the butten interaction but my hud power butten did not change colour neither did the power turn off. I tried restarting the server, no luck fixing it, restarted my game, no luck there either. After about 20 minuites of panicing and looking through forums i decided to try and detach the merge blocks and as soon as i detached one it let both my large ships( in space with zero p-gravity) and the small grid ships where my friend was back on Earth-Like function completely normally as if the bug never happened.

This is the steam forum my friend posted to try and get help.

https://steamcommunity.com/app/244850/discussions/0/4939856028581357460/