Firefox 52 ESR issue with Pop up for NTLM authentication

Question

Hi all, 
 I wonder if anyone here is having a problem with NTLM authentication problem for Firefox 52.1.1 ESR and Sophos UTM running transparent mode? 
 We recently pushed out Firefox ESR version 52.1.1 update to a test group and they are all having the same problem with the pop-up window asking for authentication credentials. 
 We have followed this link https://community.sophos.com/kb/en-us/123362 to set network.automatic-ntlm-auth.trusted-uris Things have been working fine until this update. The setting did not get wiped out due to the update. We have removed the URL, restart firefox, re-enter the URL, and restart the firefox again. That didn't make a different. 
 
 Thanks, 
 Matt

BAlfson · Accepted Answer

Others have reported here in the last week that this problem also exists for 53 and the 54beta, Matt. Apparently, downgrading to 52.0.2 is the solution at present. 
 Cheers - Bob