Looking for some help and insight here on a basement bathroom problem.

I have a basement bath and shower hooked to a sewage ejector basin. I also have a separate sump pump in a different corner of the house. Over the last few months, I've noticed the sewage ejector pump going off every 3 hours or so even though the bathroom and shower are seldom if ever used. The system is a good one with a fairly new pump installed (last 2 years), proper venting and pumping into the septic system. The front sump pump very seldom goes off and works fine.

I took one of the plugs off with a plumber who first suggested a bad check valve or a lead from the toilet. However we noticed a steady trickle of water that seemed to be coming from the basin itself. He said its very rare but could possible by a crack in the basin itself allowing external groundwater to seep in. Has anyone ever heard of this?

Solutions he offered were to initially monitor and see if its just temporarily high because of all the snow we have had, but that we may need to try and patch the leak with fiberglass or a cement patch. Alternatively he said we may need to change the whole basin which he said was a large expensive project.

Any thoughts on what to do here? I'm also concerned that if I do patch the leak or replace the basin, won't that groundwater simply pop up elsewhere under the house?

Thanks