QCA6174 power save disabled but STA goes to sleep after association or channel switch

[SEDE]

Hi all,

Does anyone have a clue on this one?

I tried to disable a lot of features, including U-APSD, adaptive OCS and 
obviously PS mode,
but still I continuously see these 2 QoS NULL packets being transmitted 
about 2 seconds after association (or following a channel switch),
indicating the QCA6174 is paused for a few milliseconds.

If I disable QoS, I obviously do no longer see these 2 frames, even 
though it is still reported in WMI events that the QCA6174
was paused by the multi-channel scheduler. However, this is not a 
solution for me since I do need QoS for my application.

Help would be highly appreciated on this one.