Mikrotik cuts speed over Wi-Fi in a bridge with ethernet ports - what could be the matter?

Question

Mikrotik

Good evening! Today I encountered a very strange problem, all wifi network clients have an incoming speed of strictly 1 Mbps, it seems that there is a limit, the outgoing speed is 30 Mbps. On ethernet, the speed is as expected 30 Mbps in both directions. Wi-Fi and ports sit in the same bridge. There are no rules for the restriction, the router was stupidly configured through quick settings and worked in this mode for more than a year.
What I did - updated the firmware, created a separate bridge, stuffed only wifi there - everything is fine, the speed is maximum. As soon as I add an ethernet interface to this bridge, the speed drops strictly to 1 Mbps. I went through all the menu items - nothing unusual - the standard config. The question is, what could be the problem? First time I see this...

Answer 1

Reset the router, the result is the same! I did this: two bridges, one ethernet in the second wifi. Networks see each other. Very strange behavior of the router, how many years I have been using it - I see this for the first time.

Answer 2

put only n