NBM 3.7SP2 on NW6SP2

Clients: Win9x - Win2k, several versions, most IPonly, few IP+IPX
NWClient: 3.32sp2 + 4.83sp2, English and German

more than 3/4 of all users have a problem
using CLNTRUST (1.4) authentication to
the bordermanager, when they open any page
through the proxy:

They are presented the SSL NBM Login Page.

2 things 'solve' this:

1.) ignore the SSL page, just retyping into
the URL line the desired address works
mostly, if not:
2.) dwntrust, clntrust, access that URL again.

For those clients facing this problem CLNTRUST
shows 1 (exactly 1) failed access. After retyping
the desired URL its 1:1 success:fails.

Thanks for any suggestion,