I didn't test it with disabled Bluetooth. So cannot provide correct information.
However, there is some update on the issue. Recently (4 days ago), I have rolled back to default kernel 4.18 and updated atheros firmware to one from kvalo (QCA-ATH10KwWLAN.RM.4.4.1-00128-QCARMSWPZ).
By now, the issue haven't occurred at all.
I didn't test it with disabled Bluetooth. So cannot provide correct information.
However, there is some update on the issue. Recently (4 days ago), I have rolled back to default kernel 4.18 and updated atheros firmware to one from kvalo (QCA-ATH10KwWLA N.RM.4. 4.1-00128- QCARMSWPZ) .
By now, the issue haven't occurred at all.