This KB points to the improvement changes in code via PR, to modify the raising of "IIC access Error" alarm.
Sep 19 15:14:43 fra10 alarmd[25255]: Alarm set: RE id=805306473, color=YELLOW, class=CHASSIS, reason=RE0 IIC access Error
Sep 19 15:14:43 fra10 craftd[22206]: Minor alarm set, RE0 IIC access Error
Via the PR1816912, new counters were added so that only during 3 consecutive read fail it should raise the alarm.
And after 3 consecutive read success it will clear the alarm and the errors .
Simliarly for write, it is one cycle.
https://prsearch.juniper.net/problemreport/PR1816912