Can retro pass text or date run results to the retro element?

Summary:

The retro process will pass integer and money values across to the retro element. But text and date run results don't appear to be passed.

Content (required):

We have modified an earnings element to record the effective date in a run result in order to improve the visibility of this information when viewing on screen and in reports. This is done simply by returning the date from the fast formula and storing it as a direct result in an input value.

But, when that element retros, only the numeric values seem to be passed to the retro element (the retro element has an identical input value that could quite happily accept it). Whether we store the date as text or as a date field, it is not being populated in the retro element.