What you were expecting to happen, and what actually happened:
I was in a Guild Wars battle, and had been using this troop. It had been exploding a column. I don’t have a screenshot, but this video shows the ability I had seen: https://youtu.be/w_MwjM7adaU?t=38
After using it once, the next time in the same battle, the ability changed to that as screenshot.
How often does this happen? When did it begin happening?
All the time since it flipped earlier.
Steps to make it happen again
Open this troop to see the ability maybe?
I checked patch notes and the balancing changes and don’t see this.
I had the Daemonic Sentinel on my team. It had done yesterday’s guild wars with that troop, and it was exploding a column then. Today, I used it for 1 or 2 battles, then on the next battle, I had the troop cast its spell at least once. The next time its mana was full and I went to cast it, I didn’t get to select a column and was confused, so I checked and the description had changed. I find it weird in particular that it changed mid-battle.
Happened to me too and I lost my last battle because of it. No bonus of 500 points and we might lose the day because of that bug, because several others in my guild used the troop too.
I don’t recall. It is the current GW event in Blighted Lands though.
I checked today, and Daemonic Sentinel is showing that it explodes columns again, both when I check my troops, and when I choose Guild Wars.
I swapped out the troop for another that fit better with my other troops after the ability got changed, and don’t want to swap it back in. When it switched mid-battle yesterday, I almost lost the battle because the new abilities no longer worked so well with the rest of the troops.