I have RB2011L-IN, and I have a problem with it.
The problem is definitely with versions 5.19 and 5.20
Problem: Random stop working ports 1-5 or 6-10. (All ports have configured in bridge.)
At the time of the issue reports MikroTik connected devices at ports, but there is no transmission. It helps to restart (but not always), and the disable and enable of any port in the group - transmission occurs on all ports.
Is that a problem firmware / firmware or damage to the equipment?