Ive noticed this since I made the higher flow mod to my LQ: one day I can set the flow at 3 on the flow meter. Everything seems to work fine, no air in the system, etc. Enough flow that I can peg the meter if I want.
Let it run for the rest of the on cycle and its fine. The next day Ill look and see the flow meter at 2 or lower. Nothing changed, just the fact the filter/pump cycled off and then back on. Ive also checked after the filter was running for a while the next day just to be sure it wasnt a priming issue as the pump started up.