Symptom:
Roaming delays up to 10 seconds are observed on AP1262 in WGB mode running a special ap_p build with HSR fixes.

The delay is observed on the "debug dot11 doX trace print uplink":
Apr  2 10:49:05.662: %DOT11-4-UPLINK_DOWN: Interface Dot11Radio0, parent lost: Signal strength too low
Apr  2 10:49:05.662: 11B818C3-0 Uplink: Lost AP, Signal strength too low
Apr  2 10:49:05.662: 11B81948-0 Uplink: Wait for driver to stop  <<== start here
Apr  2 10:49:15.442: 124D83D7-0 Uplink: Enabling active scan    <<== scanning 10 seconds later
Apr  2 10:49:15.442: 124D83EA-0 Uplink: Scanningnt.

Conditions:
AP 1260 in WGB mode roaming across FlexConnect local switching AP on Open SSID with sustained traffic in uplink (video feed).