My Accord 2013 A/C clutch would not engage until after 10-20 of driving. But after it is engaged, the cold air coming out as normal and works fine from then on. Shut down engine and restart immediately, A/C clutch can engage immediately, but if restarting engine after 1 hour, it would take another 10-20 min driving to make a/c clutch engage again.

I checked A/C relay, good.
Checked low side pressure when clutch is engaged, it moves up and down between 20-45 psi within blue zone of the gauge (meaning normal?)

What could be the issue?

Thanks a lot in advance!