What could cause a water pressure dip at the cut in pressure?
Reduce the differential - raise the cut in pressure to 52 or 53. Or lower the cut-out to 62 and play with the air pressure in the tank, perhaps - I'm familiar with how bladder tanks behave, and got most of any answer written before noticing that you mentioned a diaphragm tank, specifically.
30PSI is an unusually large differential pressure (20PSI is what most tank charts assume - 20/40, 30/50, 40/60 and most pressure switches come pre-adjusted for that - but most are also adjustable. Read the directions for yours, and remember to turn off the breaker supplying power to the pump circuit before removing the pump control's cover)