Assigned template problem

[baladeva]

hello to all,

some time when someone has send a pm to me, and when i enter the site, there is the message:
you have one or more messages, some think like that - then we can click ok - and go to that message,

so fare no problem, but some times  (sometimes only - not always)
when i click ok, my template is not proper assigned - means the template is not like it is usually for the forum, without the menus left and right; and the css is also not propper;

i am not sure if other users have this also, or only me as admin