White mushrooms are taken from real mushrooms that multiply by exploding, just explosion range for them there is set much higher
Yellow wisps remaining after big pyramid is intended, Rozital Spider Scout things are supposed to take the remaining ones
Drives exploding is probably intended, if drive gets damaged too much it will explode on use, to avoid players just throwing the drives around
I also noticed that the spawn rate for mushrooms it a lot higher, on 0.6.3 even after 30 days there just about 10 of them, but on 0.7.0 even on second week there is more than 40 mushrooms growing around, this is probably a bug, because I don't think the roof is supposed to be fully covered in mushrooms
Buckets moving through walls was a bug even in earlier version, I think they move only when player far away or on save & reload