Air BR Airfield AA not working?

I just had a match and we were in a 4 v 2 (us) over our own secondary airfield, one of us got shot while on the airfield, and the aa of the airfield did barely anything. The enemys were 500m up high maximum.
I am used to it being that planes get shot down relativley quick when over the enemy airfield.

Session: 13b71cf0028fa63

There are some maps with non-working af aaa.

Most famous is Golan Heights…