Hit a plateau

Hello, I’ve hit a plateau on my incline Smith bench press.

What’s puzzling me is that every other exercise I do has been progressing either in terms of reps or weight every session.

I do incline Smith bench press every two sessions, twice a week, and perform a simple 1 working set to 0-1 rir. This system is applied to every lift, and I’ve noticed steady progress on every other exercise I do.

However, I’ve been stalled on my incline bench for four months now.