When you delete the core of a damaged ship it asks to reboot after you've confirmed you want to destroy the core, leaving you with a temporary ghost ship (it will destroy itself after a few seconds) as well as an empty ship stats dialog if you enter build mode afterwards, even in another ship. The in-flight HUD also seems to be affected. On top of that block orientation in build mode seems to be in relation to the deleted ship as well, even when in other ships.

Steps to reproduce:

1. Spawn a core
2. Enter build mode and place a warhead (I did it a few blocks away from the core)
3. Detonate the warhead
4. Delete the core from within build mode