Hi @Abhishek Dewan,
i think i found the root cause - i can't edit any entry - from these i imported long time ago - ( i think from keepass ).
All these entrys have a custom field called "Notes" - and the problem is not the content of the fields,
but the field type - as you can see here - the field notes has no data type.
When i choose text here - save the entry - and edit it again - its working.