Alien hidden under maptile or entering solid objects

A Scylla dropped a Mindfragger. That was over a map tile with a plant on it.

Mindfragger got hidden, until I shot the plant away.

This one is a known issue. Happens with Mindfraggers deployed by Scylla and worms lobbed by Chiron. Apparently an ongoing bug that they have tried to fix before, and are continuing to work on for the next update.

And again it happened:
Chiron launched a lot of times towards a high building.

Acid worm got stuck in a building piece.
Had to kill a stunned worm, because otherwise game wouldn`t show me the position of that last worm.

Holy crap, can`t finish a mission, because a Chiron decided to enter a tree-like structure on a citadel mission.

Structure is indestructible, thus mission can`t be finished.

Chiron was in panic.