I’m having an issue where attempts to heal Sid don’t work under any circumstances. Neither the base Stim skill, the Stim All (whatever it’s called) skill, nor the Stim Grenade will heal him. Further, even his own passive skill that allows him to heal 10% at the start of each round isn’t happening.
I’ve noticed weirdness around the healing skills in general. I have never seen the AoE Stim Grenade heal more than 1 person, even when multiple injured soldiers are within the radius. Other times the Stim skill simply has no effect, else I’m misunderstanding how it’s used. Is there supposed to be a range, e.g. “must be adjacent to target”? If no, it shouldn’t proc and be wasted if the target isn’t adjacent.
If anyone else sees similar behavior and finds a fix, please do let me know.
Overall, though, I am really enjoying Gears Tactics! I do wish there was a strategy layer a la X-Com, but the tactical layer is really well done and feels more intense than any turn-based game I’ve played (which is pretty much all of them). Maybe in 4 years Gears Tactics 2 will include a strategy layer where you fight for control over territory like the old Jagged Alliance games. 
EDIT: While I don’t completely understand the mechanic yet, I don’t believe the lack of healing is a bug. It’s in some way related to a soldier having to be revived during the mission and subsequently unable to heal past a certain point. For instance, If Sid has 3 health pips when he goes down and requires revival, he will thereafter only be able to heal up the full 2nd pip but not the 3rd. In the UI, the third pip is shown greyed out with a faint red X in it. I can’t find this documented anywhere and it wasn’t mentioned in the tutorial. If someone can explain exactly how the mechanic works, I’d be grateful.
I’m facing the first boss on ‘Experienced’ difficulty and have 2 soldiers down a pip going into it, and I’m just getting my ■■■ kicked. I’ve lost and restarted the boss 10 times. I’m going to try to run the whole mission again and get to the end with all soldiers at full health and give it another go (I’m NOT confident, though, because I’m not even coming close to beating him). If I can’t get it, may have no choice but to drop down a difficulty level, which would suck and make me feel half a man!