I know this thread is old but I was having a similar issue with cached AD authentication credentials. I found that the SQL service account (AD account) was using cached Kerberos tickets and not getting updated info from AD. This is on the OS end and there isn't anything in SQL that will refersh this. However I found I can run:

EXEC xp_cmdshell 'klist.exe purge'

which purges all Kerberos tickets for the current user. Since xp_cmdshell runs under the context of the service account all the Kerberos tickets were purged and new ones generated. This solved my problem and I hope someone else will benefit from this info too.