HPOO 10.51 not displaying user prompt when executing Manual Operation

Greetings Everyone, My apologies if this question has alerady been answered before. I could not find a similar hit when I searched.  Now, to my question.   We are executing a workflow that executes a "Manual [Operation]"  from the " /Base [1.6.2]/Library/Utility Operations/Manual "  content pack and recently it has gotten stuck intermitently in the step that prompts the user for a " Yes / No "  answer.

When I look at the previous WFs that ran successful and prompted user for answer, I noticed that there was not Worker ID associated with this Manual Operation prompt.  

is there anything I can do to make sure the prompt is displayed consistently?

I rebooted both the Central and NRAS ( including Oracle Db servers )  and still shows this intermitent behavior.

thanks for any tips/guidance you can provide,  oscar.