Quoted from ABE_FLIPS:I also have had problems with the soul gem mode and mind gem usage.
The display says i have one use on mind gem, so i hit that shot to activate the action button but nothing happenes.
You do not need to hit the shot to activate the action button. If you have a use remaining, it doesn't need to be qualified first. If you are out of uses, then the gem needs to be moved or re-placed (or the Avenger who has it leveled up) to recharge/qualify it. You cannot do that during Soul Gem mode.
During Soul Gem mode, if the Mind Gem is placed on a non-powered up, uncollected or collected Avenger, it can only spot a hit to the Avenger that has it. If that shot isn't the lit one, nothing will happen since the shot where the gem is placed isn't lit for anything. Otherwise it would just be a waste of a gem use. For example, if the Mind Gem is placed on a collected or uncollected Black Widow, you can only use it when the Black Widow shot is lit (the second shot of the Soul Gem mode).
If you want to be able to use the button to spot ANY lit shot, the Avenger who has the Mind Gem needs to be leveled up to level 1. That allows the button to collect ANY lit shot as many times as you have usages left. For example, if the Mind Gem is placed on a Level 1 Black Widow, and you have three uses remaining, you could use it once to spot Black Panther when lit, then once on Black Widow when lit, then once on the Gauntlet ramp when lit. Or any three shots that you choose, but only while that shot is lit. They do not have to be three in a row. In my case, I struggle most with Black Panther, the drop targets, and Captain Marvel during this mode, so those are the three I would hit the button for in this situation.
Having the Mind Gem on a Level 2 Avenger is not great for Soul Gem mode. At level 2 the button will collect ALL lit shots at the same time, which for Soul Gem means one shot only since only one lights at a time. In some modes where there are a bunch of shots lit, this is awesome, but in Soul Gem it's a waste, unless you really need it to hit that one shot. For example if the Mind Gem is placed on a Level 2 Black Widow, and you hit the button right away when the first shot, Black Panther, is lit, it will collect only Black Panther, since that is the only lit shot. One use only, so if you have to use it, use it on a shot you struggle most with.
Bottom line, if you want to use Mind Gem during Soul Gem mode, you need to wait for the Avenger who holds it to be the active shot, or you need to level up the Avenger who holds it to Level 1 (or Level 2, but the "collect everything lit" ability will be wasted).