What can cause this "wifi: tx null, bss is null"

[marjonz]

I am currently using an ESP32 WROVER chip, and periodically puts the chip to sleep (to save power) for about 10 mins. When it wakes up, it checks if an access point is within the vicinity and tries to connect to it. The weird part is that the chip can get into this state where it fails to connect to the access point and keeps logging this error message. The only way to recover is to power cycle/reset the chip, then it will be able to reconnect to the accesspoint.

Does anyone know the meaning of the debug message?