Hello, machine translation (‘jerk’ No offense intended, just turns out fun sometimes). But more seriously, this is a known issue:
That’s how it has always worked, and it seems to make sense: once you ‘take control’ of a minion, which is what the ability does, the creature no longer ‘controls itself’, losing its queued ability. I don’t see why we should consider this a bug — seems like a design choice, arguably.
And what, a controlled creature should not have its own move?
When you take control of a creature, it binds to a mercenary, tie Kthun’s tentacle to Nzoth and make a move at speed 5 with a tentacle and then again with 2 Nzoth’s ability and it will work, and after all, the tentacle is a controlled creature of Nzoth from the last turn.