I am not sure how often this happens exactly, or what causes it, but the current Avengers vs Ultron event brings up a reminder that the game seems to often auto select the lower tier version of required characters when multiple tiers are boosted. Ex: I have a 5, 3, and 2* Black Widow, but for her essential node, the game selected the 2* version. I would prefer if it defaulted to the highest tier version of the required character.
If boss events are are going to be more frequent (a good thing), perhaps this could be looked at. Boss Events are the only PVE Events where multiple versions of the same character are boosted at one time.
It’s kind of random, really. I had it select HulkBuster for the IM node, and I have all four IM variants, so it’s not just picking either the highest or the lowest.
So when a variant of Iron-Man is the required character, you tap the currently selected Iron-Man in the ‘required’ slot, and all possible Iron-Man variants move to the front of your roster with every other character being greyed out.
I have two level 1, 1* Black Widows with only blue covers. For the Black Widow node, the game would always auto-select one of my 1-star Widows. Fortunately GSBW was boosted so she was on the 2nd or 3rd screen for me, so it wasn’t a big deal for me to select her, but it was still annoying to have to do it every time I did the Black Widow node.