I guess it works now.
May be they have some predefined defaults for such devices ?
So users report lower signal after upgrade...

*) wireless - improved antenna gain setting for devices with built in antennas;

What it exactly means?

This "feature" has been discussed here already :
viewtopic.php?f=7&t=143720

The issue is not with the standard, it's with the chip. In this model, both 2GHz and 5GHz are run in the same wireless chip, which doesn't support such features as showing all the powers. Hi Normis, What other features are not supported at the moment for hap ac^2 ? Setting manual-tx-power ? What ar...

Why it is not supported ? Is Manual TX Power also not supported ?
And do the regulatory domain actually correct the TX power ?

I can confirm this issue is present on my hAP ac^2 also. Version 6.43.8.

Can someone running 6.42 longterm comment if they see similar behaviour ?

I see this as a major issue that needs to be addressed by Mikrotik Support !

Pavlan how many ports do you have on your bridges?

On the 750G - two corresponding vlan interfaces. But its not config issue.
I've seen these strange readings in host table on various devices.
Especially mac addresses appearing as 00:00:00:00:00:00.

There is a bug in 5.20 bridge !!! I checked several boards running 5.20 and all of them show strange results in bridge host table. i.e. this is from a 750G BRIDGE MAC-ADDRESS ON-INTERFACE AGE bridge-vlan32 00:0C:42:1D:xx:yy vlan32-eth3 0s L bridge-vlan32 00:0C:42:72:xy:xy vlan32-eth3 0s .... ... -> ...

not for me

i was using 4.14 already

I came across exactly the same problem today... I updated a RB532 with two Atheros 5213 minipci to 4.14, enabled wireless-nv2 and reconfigured the link from nstreme to nv2.. Ran some tests and everything looked very good.. but a couple of hours later i came back and saw that the AP had just rebooted...