It looks to me like there is a leak and the continued splash-back into the sump is because the check valve is not stopping the water from reversing back down the pipe. Does that splashing continue indefinitely with the pump plugged in? What happens when you unplug the pump after the water level reaches a minimum?

While awaiting answers, I think you have a simple leak and it is above the check valve.

A small hole is often needed to keep check valves working (between the pump and check valve) but that is a lot more water than they release.

A hole as small as 1/8 inch os often enough if the water is clean.

Dirty sump water can cause problems with check valves sticking and bleed holes clogging.

Thanks for the feedback. It turned out that the pipe that screwed into the sump pump was cracked between the threads and the pipe. It would stop leaking if I pushed one way on the pipe, and the sheered off when pushed the other way haha. I replaced it and its running much quieter now. It does have a 3/16" hole drilled to prevent "air lock". Thank you both!