I'd second (third and fourth) the idea that frequency might be the answer here. Pressing and benching once a week lead to stalls on both. Adding in a lighter press and bench as assistance work seemed to unstick them, mostly.
I do the lighter lifts at a weight where they will definitely go up and not grind, well not too much. I do three to five sets of five, adding a set each week and then increase the weight, if I feel ready for it. Probably don't need the extra sets, but it feels like progress.
Technique faults can also make a big difference. A slight forward travel of the bar can be recovered on the first two or three reps, but if it deviates from mid foot at the end of the set, it will stick at just above eye level.