For what reason can coolers stop?

Question

Processors

I welcome everyone!
The ASUS PRIME X470-PRO motherboard has a Ryzen 3600, be quiet! DARK ROCK 4.
PSU - Sea Sonic Electronics FOCUS Plus Platinum 550W.
Add. coolers:
- two Thermalright TY-147B, 140 mm, blown on the front;
- on the back there is one noname cooler, 120mm, blown.
All but the last one on the list are connected to PWM.
Yesterday I noticed that the CPU cooler is not spinning! I went into Aida - the CPU temperature is 60-65 degrees in idle (usually 40-50), rpm 0, of course. I reboot the PC, the cooler works correctly again (400-500 rpm), and after an hour it stops again. I thought that the problem is the following - the cooler on the front is located strictly opposite the processor one and the system "thinks" that there is sufficient cooling (the case blows directly into the CPU cooler). I decided to warm up the PC with a stress test to test the theory. Test result: CPU 80 degrees, CPU cooler did not start, and in addition one of the blowing coolers turned off! I don’t want to think that the problem is in the recently purchased hardware with difficulty. Perhaps the settings in the BIOS are incorrect, what do you think? There is a "QFun tuning" setting in the BIOS, in desperation I tried to apply this setting,
And the last thing - before installing two Thermalrights on the front panel, there was noname 130mm in the center, and it seems to me that there were no problems. Attaching photo.
Before installing new coolers:

After installing new coolers:

Answer 1

And again, under load, the CPU cooler and 1 rear cooler stood up, the CPU temperature was 94 degrees. I reset and updated the BIOS firmware, disabled PWM (the only thing that helped, but it became noisy), etc.
Removed, installed HWMonitor, a couple of weeks of tests, all fans work properly, everything is in PWM mode.

Answer 2

BIOS can be reset and flashed. but if the problem is inside the mother or the power supply, then just try it on another bp. and on another m.p. trite somewhere in the chain.

Answer 3

The BIOS settings must be reset to default, there should not be any special modes for coolers - set all the most stupid and unambiguous. If it doesn't help, it makes sense to consider an even more frontal option - a cooler malfunction. The most common is drying or hardening of the lubricant (99.9% of all cases). How to restore it has been described on the Internet a million times.