Water “rushing” to sump, not check valve?

Wondering if anyone can help me determine why water seems to “rush” back into my sump after the pump runs. In the video, you can hear a constant trickle from our French drain, but it turns into more of a waterfall for a few seconds after the pump runs. The pump runs very frequently (every 30 seconds or so during wet conditions).

I initially thought it was the check valve, but when taking it apart, the valve did seem to be holding back water (and seemed in tact upon inspection). Is there any other possible cause or is it just the check valve and I clearly know nothing about plumbing?