I do it around once a week as im on the anti flamingo prgram. I reckn it might be due to my weight as the past couole of weeks its kinda been fluctuating downwards and iv heard that bodyweight has a high impact on pressing strenght compared to other stuff. Not sure how true that is tho
It might be a slight factor, cant be sure tho. I wonder if its possible that you train pressing exercises too infreqently. I guess you have to experiment to find out. If you only do Push 1x week you surely will have to be well recovered I would assume. Maybe you need more stimulus.