Checks that don't tell you what you were even being tested for.
My first run of Nastizia's suitor thingamajig had me win the "honeytrap" trial without any indication on what that was even about. Reading the dialogue only clued me in that Captain Steele told someone "no" politely and won.
On my second go I failed the check and lost. I tried to look back, and Steele fell for the trick of that particular trial. "Weird" I thought to myself, and then I checked the Wiki to see that it was a willpower check.
This is a problem I see with a lot of scenes. Some of them seem obvious, like playing against Syri in Call of Valor being an aim check, but then the dialogue is misleading. "Watch your ass" oh, so I need reflexes? Wiki says nope, aim.
Taking a step from stats for now, I just tried to increase my character's willpower by training with Mirrin, but she turned me away, not saying exactly why. I could only guess it was because my character is a centaur, but if the game showed in bold "Check Failed: 'Taur" then I wouldn't have to frantically check the wiki to-
Oh, that's right: that isn't addressed in the wiki as of writing this.
Solution? As I said earlier, displaying some text that indicates what check I failed would do wonders for save scumming repeat playthroughs where I want to pass that check the second time. Of course, there is still the problem of some stat checks being randomised, but that's a topic for another post. Point is: something like "Check Fail: Low Aim" or "Check Fail: Wrong Species" (and appropriate dialogue for passing the checks if the player succeeds) would help a lot with communicating what the game wants from me.