Close to give up on my Omnias :(

I was thinking what was different when I took TO to cz.nic - I changed password to a weaker one. I tried to setup another wifi network with that weaker password - I connected my phone to that test network and it looked promising for a while but then my phone disconnected and connected to the other wifi network on the same card. What was interesting was that the phone stopped seeing the test network while it was connected on first one (the same radio and antennas … )

As I was watching logs and wireless tab I noticed some clients appearing and disappearing (with relatively strong signal) When I checked the logs I could see that phone of my wife connected and disconnected within 7 secs due to inactivity. 7 seconds is really a short period of time - any idea why it could happen?

2017-03-20T22:28:40+01:00 omnia daemon info hostapd[]: wlan1: STA xxx IEEE 802.11: authenticated
2017-03-20T22:28:40+01:00 omnia daemon info hostapd[]: wlan1: STA xxx IEEE 802.11: associated (aid 3)
2017-03-20T22:28:40+01:00 omnia daemon info hostapd[]: wlan1: STA xxx RADIUS: starting accounting session 72176B96C90FE253
2017-03-20T22:28:40+01:00 omnia daemon info hostapd[]: wlan1: STA xxx WPA: pairwise key handshake completed (RSN)
2017-03-20T22:28:44+01:00 omnia daemon info hostapd[]: wlan1: STA xxx WPA: group key handshake completed (RSN)
2017-03-20T22:28:46+01:00 omnia daemon info hostapd[]: wlan1: STA xxx IEEE 802.11: disassociated
2017-03-20T22:28:47+01:00 omnia daemon info hostapd[]: wlan1: STA xxx IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)