I'd really prefer to run server psu's because they are designed to go at 100% 24/7 so finding a solution to this would be great.
All properly designed PSUs work just fine at near 100% load for 24/7/ten years.
Apparently the power controller sees something wrong and powers off the PSU. Only that controller (not the power supply) decides when a PSU powers off or on.
Apparently a manufacturing defect in that one PSU is detected by the power controller. To say anything more (that is not wild speculation) requires numbers.