Low-freq feedback onstage (especially if it is coming from the FOH subs) can be difficult to catch from a challenging FOH position. As a performer I have had several experiences with a severe "wrap-around" from a FOH rig where the "whooom" onstage was already deafening before the the FOH guy caught it. In one instance the guy was oblivious to all of our waving and gesturing, until the lead vocalist finally hollered over the mic about it.
It is far more important that you maintain eye contact with the musicians rather than the console. Just a simple fact.
Sometimes, it's the room. I played a large, national chain, well-known (recently closed) "Country" venue in Dallas a number of times over the 18 months it was open. Line array FOH, EIGHT dual 18 subs under the concrete stage, Midas Pro2-TP console, 1000w stage mons + dual 18 Drum sub, and wood facia stage walls.
Sounded freakin' AWESOME out front, but the low end bass "boom/rumble" resonating around the stage from the combined subs was absolutely horrible. We were not IEM back then (different band) so used the stage monitors. Great mix on those too, but it didn't matter WHERE I stood on the stage (I was wireless) that rumble was still there. It became confusing when playing the Low B (5-string bass) because it was hard to tell what I was actually hearing...
Yes, the FOH guy (Stoney Larue's former FOH) came up, listened, tweaked, adjusted and finally gave up saying it was room dynamics. Happened every night we played there... I just had to deal with it...