CRS328-24P-4S+ overheart

Or not?
Have two same
Hardware: CRS328-24P-4S+
Operating System: Mikrotik RouterOS 6.45.7 (Level 5)
current-firmware: 6.45.7
both cpu-load 5-7%
but one have temperature CPU 38-39C / SFP 33-37 / fan speed 0 rpm
another have temperature CPU 47-54C / SFP 50-57 / fan speed 0 - 1300 rpm
Inlet air temperature 19-21
next to this overheated router cisco with SFP modules temperature 37-38 (CPU temperature can’t grub)

So
Is it normal, FAN RPM 0 if temp <40C
Is it normal temperatures for liteloaded CRS328-24P-4S+