Hi John,
Would recommend to contact TAC for this for them to analyse deeper and possible to check from remote tunnel access to check whats going on.
However we do have defect CSCuu49389 (fixed in latest GD release) that is similar behaviour that you mentioned and have certain cases the you need to issue multiple "proxy kick" command that you did before to resolve it (have some cases that it will not fix it if only perform one "proxy kick" and need to do it few times.
Also please make sure that there is no configuration mis-match for this and make sure the correct user is listed in the accesslogs and there are policy configure for this user/user group.
Regards
Handy Putra