A comment :

Since the LSC RFPD have a long cable of more than 6 m, which rotates a 33 MHz signal by more than 360 deg, so the delay has always existed in everywhere.

The circuit you measured is a part of the delay existing in the LSC system, but of course it's not a problem as you said.

In principle a delay changes only the demodulation phase. That's how we treat them.

RA: Actually, the issue is not the delay, but instead the dispersion. Is there a problem if we have too much dispersion from the RF filter?