Does not conform to online banking

I think IE8 is a great upgrade but I have found problems with online banking websites I get an Invaled Session warning and have to login several times before entering accounts.
Had this problem, with the beta version of IE8
the banks told me they have not resolved the issues yet and told me told to go back to IE7 which had no problems, well I tried the release version of IE8 and the old problems are back.
Has anyone else had problems with security login on banking or credit card sites?