Hi,
How have you placed the webpart into that page? In the Portal Engine or in the ASPX code?
I would maybe recommend to check the discussion under
Martin's Blogpost, where he states:
There are also two known issues with the original implementation. They are:
1) Output cache is not stored separately based on the cookie level
2) In some special cases, some cookies may be initialized upon the first request to the web site even when they are above the allowed level. We identified shopping cart coookie and current contact cookie so far.
Both will be fixed in the upcoming hotfix 6.0.34
Which hotfix version are you using now? This might be related to the behavior you see...
Regards,
Zdenek