Probably one of those huge safeties, like my para.
Like he said above, there is a spring in the plunger tube that does double duty. Pushes detent pins to bear on the detents of the safety and slide stop.
Pretty easy fix. For a single side safety look up some YouTube,
Same for a ambi.
Sometimes a different profile on the detent pin is needed, or a new spring. I fixed one of my paras that had the opposite issue, the safety was a bear to move to safe position. I pulled the parts and smoothed the head of the detent pin