Hello,
It is a weird issue. The signal parameters are rather good, yet the logs indicate frequent mobile disconnects, which apparently, follow wireless configuration changes.
It shows that wireless interfaces go down after some configuration changes every few minutes, 5 or 6 times within 15 minutes. Can you confirm that you have changed the configuration?
Also, in your provided file, the associated networks with wireless configuration are mob1s1a1, though it should set as lan.
If you have upgraded the router with Keep settings option enabled, I would suggest to try to restore the device to factory default settings.
However, if the issue keeps recurring, please downgrade to previous version, to check whether it is a firmware issue or, possibly, failing hardware.
Best regards,
Žygimantas