I seem to have found a collision of Epicor idiosyncrasies that is causing me grief.
BAQ date parameters come into a dynamic report RDD as datetime, BUT Kinetic forms don’t have a datetime picker as far as I’m aware. Values coming in from the date picker cause the report to error, ~but when I tested changing the control to a drop down with a datetime value it succeeds.~ It turns out that it only works when a constant value is set.