Is it still issues with the WIFI?

Im getting a bit stumbled regarding the wifi connectivity on Mitras (and the P4) - they are in different locations, so I am focusing on the Mitras now.

For me, it seem like its a chance game if the WIFI is working - it can work one day, and not the other day. It can work on one lamp, but not others, then the next day its switched (without me touching the lights). What can produce this inconsistency?

FW. 1.07
WIFI-WIFI: 6375
dBm: -70

Static ip, can ping, can access the webserver all the time.