Hi all,
Recently ran into the same issue. ALL R500, R600, T300 and T301 ap's with a serialnumber starting with 4717xxx and later. Which means they are manufactured from 2017 and later hhave this issue due to the flashchip that is built in the AP. The ZD FW needs to be 9.10 or higher for this to work. All ap's before 2017 will work fine. No workarroud or patch is available for this. Hope this info helps