What you were expecting to happen, and what actually happened:
The spell description says “Destroy gems in X shape” and it lets player to choose a specific gem, so I was expecting gems in the black lines in the first screenshot destroyed.
Instead, the spell destroys gems on the diagonals of the field every time regardless of which gem the player selects.
As a solution I would expect either:
A) remove gem selection option and change spell description to reflect that diagonals and only diagonals will be destroyed or B) rectify the spell so that it actually does what the description says and is consistent with other X-shape troops (Dragonian Monk, Dragonian Rogue and Satyr Hunter).
Needless to say, I assume, that B is the preferred option.
How often does this happen? When did it begin happening?
Always since the introduction of Starry Mage.
Steps to make it happen again
Use Starry Mage in a battle
The funny part is, even the lightning bolt animation in the screenshot above strongly suggests it should be destroying based on the selected gem, it’s way misaligned.
The spell does what the spell says. Initial gem selection is superfluous and as OP says should be removed, or have the spell/troop changed improved to the “X marks the spot” type (of which there are multiple precedents).
The pattern being destroyed looks identical to what Dragonian Rogue used to destroy with the “destroy gems in an x shape” before it was patched to have targeting and function similar to the spell Dragonian Monk has. It is very likely two versions of the effect exist and the wrong one was paired to this spell but with the “needs targeting” flag still ticked or something (I don’t know what their API for inputting spells looks like, but probably something similar).
Same thing with all the multiple targets effects of the new immortal troops that don’t retarget if something dies - they are very likely using deprecated targeting processing of spells that had to be left in for legacy reasons but shouldn’t be getting used for new spell releases.
It doesn’t explode, it DESTROYS the x-shape, including the corners and middle 4.
I actually don’t mind the spell working this way because it destroys more gems (16 compared to 8-14), and gives us more mana than the usual “destroy an x shape” troops. But it’s almost certainly not what the devs intended, and it’s very confusing.
I do mind the spell working as it does now, though.
Guaranteed 16-gem destroy, in my eyes, is not equal exchange for the loss of board control when player can select where X is placed. In current (very likely buggy) spell implementation the troop is 99,9% useless and I would never ever put it on my team; heck, I’d rather take Peasant than Starry Mage, given a choice.
I can’t say I expected swift resolution, but no acknowledgement of the quite obvious issue at all? No “nothing to see here, move along, working as intended”; no “reported to the development team”; not even “provide your invite code”.
