Using steam engines, but I haven't progressed far enough on this seed to test other engines. After digging out regolith, steam engines still act as if they are entombed. Note that gantries are retracted and the rocket is mid-way through refueling.
Saving and reloading fixes this, but it reoccurs once the rocket becomes entombed again.
Never used to encounter this problem, started popping up after the Breath of Fresh Air merge update. Playing on vanilla, although I have the DLC downloaded.
See attached photo in post. Rocket works after first being built/loaded, but will be entombed indefinitely after first entombment.