I received the file, thank you. This situation is definitely atypical. I couldn't reproduce it with my equipment so, I started looking at what could cause the entries in the system.log.
First, there is a strange option in the wireless config, sta interface section (excerpt from /etc/config/wireless; abridged):
option network 'wan'
option device 'radio0'
option user_enable '1'
option mode 'sta'
option disabled '1'
The highlighted options are contradictory; I suggest removing option disabled '1'. Since it is unclear how it got that way, you'll have to remove it via SSH/CLI. Simply log in and execute these commands in order:
uci delete wireless.@wifi-iface.disabled='1'
(first one deletes the option, second commits changes, third restarts WiFi.)
Another thing I noticed in the logs is that the other access point is possibly ignoring the authentication requests from the RUT950, as indicated by these timeouts (excerpt from system.log; I just added dummy MACs and SSIDs):
daemon.notice wpa_supplicant: wlan0: SME: Trying to authenticate with 00:11:22:33:44:55 (SSID='Your_router' freq=2462 MHz)
kern.info kernel: [23504.450000] wlan0: authenticate with 00:11:22:33:44:55
kern.info kernel: [23504.470000] wlan0: send auth to 00:11:22:33:44:55 (try 1/3)
kern.info kernel: [23504.590000] wlan0: send auth to 00:11:22:33:44:55 (try 2/3)
kern.info kernel: [23504.700000] wlan0: send auth to 00:11:22:33:44:55 (try 3/3)
kern.info kernel: [23504.810000] wlan0: authentication with 00:11:22:33:44:55 timed out
I suggest reviewing that router's WiFi AP policies (MAC filter perhaps or blocked because of unsuccessful authentication attempts?)
If you can't find anything on the other router, you can try changing the WiFi Mode to 802.11g on the RUT950. This can be done from the Network → Wireless → Edit → Advanced Settings page. The reason I'm suggesting this is because I suspect the Access Point is a Ubiquiti router? I'm asking because I found some evidence on the Internet that there could be some sort mismatch with this software and Ubiquiti's and disabling the n mode might help.
I hope some of this will prove helpful. I look forward to hearing your feedback.