Portal MSS: POWL is not displayed properly

Hi,

we are facing the following issue:

In portal we start the web dynpro application HAP_START_PAGE_POWL_UI_MSS. The worklist is displayed correctly (see following Screenshot).

After opening a document with "Edit" and saving it, the POWL looks like this:

Have any of you had this problem before and know the cause and a solution?

I did not find any sap notes.

Thanks in advance.

Regards

Chris