The worklist control custom filter set during design time can be maipulated during runtime by a user and the custom filter will not longer be visible for that user who changed it during runtime.
Custom filter configured in the design time, will apply to all users, and if a user decide to customize filter in runtime this will be saved as user preference and the custom filter set during runtime will be ignored for this particular user.
First Solution - Remove worklist control, re-add control and reconfigure the filter, then disable the filter icon so that no one can make changes in to the filter in runtime ensuring that the custom filter is applied everytime the form runs.
Second Solution -The filter will be saved in the following table per user profile
If you delete the user filter from there, K2 will pick up the design time filter