Have you managed to find a fix for this?
We are not having the report on Laptops but I have had the problem occur on 2 different iPhones, Restarting the AP normally resolves the issue.
we are also seeing errors for the mac code around the time of the issue:
Client (mac='<mac code here>') on interface (value='r2v1') Ussing SSID (<SSID HERE>) recieved an Add Block acknowledgement (ADDBA) response with Status code (value='Status code 37')