For vpn-idle-timeout none I had to add a group policy via Flex Config. DO NOT add the access-list but in the group policy I had to add the  user-authentication-idle-timeout nonegroup-polic Group-Policy-X.X.X.X internal group-polic Group-Policy-X.X.X....

I just had a same issue on 7962, ring once then it would hang up, the local tech ran through and hung up all the phones in the office and service was restored, thanks

Any resolution, experiencing the same issue on a nexus 5548. I shut one SVI and then I am able to ssh to the intended MGMTsvi. I also placed management on the MGMTsvi, once I no shut the other svi all connectivity is lost