RB911G-5HPacD ethernet activated for a long time

Welcome to all!
Bought 2 RB911G-5HPacD, there is a problem on one ethernet port, it begins to work in an arbitrary time after the device boots, usually ranging from 1 to 30 minutes …
I.e. MT usually beeps when booting, and most of the devices can be pinged immediately after the tone, but this board does not respond to pings for 1 to 30 minutes after the beep.
When ethernet port finally starts working, the resources menu shows that the device’s uptime is those 1-30 minutes.

I’ve tried flashing this board using NetInstall for with different RouterOS versions, but it did not help …
Also I’ve noticed that you can not update the qca9550 firmware above 3.29.
supout.zip (317 KB)

Send email with the supout file to support@mikrotik.com