SPD 2010 Workflow "Collect Data From User" activity + Multi User selection

Question

Creating a SPD 2010 workflow. Trying to do something that I think should be simple.
Use a “Collect Data From a User” activity to collect 0 to many “people” that should be affiliated with a piece of content (Discussion).
After the assigned user completes the task (and after ensuring that there have actually been people associated from the task) I want to take the “people” from the Task list item and move them over to a field on the core Discussion item,
that is also setup as a Person/Group field (allowing multiple).
I have tried using both the “Set Field in Current Item” and “Update List Item” activities to map the data over (pulling from the Task item) and in both cases tried using every combination of “Return field as”
values to do the mapping (i.e. ‘String’, ‘Display Names, Semicolon Delimited’, ‘User Ids, Semicolon Delimited’, etc). In some cases I get vague errors about not being able to do mapping (I get it), in others, it sets the
data, but only to the first user entered in the Task’s instance of the field.
After researching a bit, I find that the task from which I am pulling the data only contains one value, eventhough when I submitted the InfoPath form for the task, it accepted my data entry of two
different users. So I think somewhere between the data entry into the custom task's infopath form, and the update of the same data field in the Task list, the value is being lost.
I am sure this would be trivial with a custom activity, but we are exploring OOB ways of doing things and I have to imagine this is possible.
Am I missing something here? This seems “buggy”…
I am able to repro this in two different environments, using an out-of-box Discussion Board on an out-of-box Team Site.  If it matters Claims Based Auth against Windows only...
TIA!
Brian McCullough

Answer 1

Hi brianpmccullough,
Collect Data from a user action can only use to collect data from one user, and if you need to collect data from one than one user, please use “Assign
a Form to a Group” instead, then it will create separate task for each user.
And if we need to update a user and group field which with multiple selections enabled, we can only use lookup field to get only the one user. And
to add multiple users to this field, we can only use String Builder, type the user account directly or get information from multiple fields.
Best regards
Emir Liu
TechNet Community Support