I recently converted a LF Form from Classic to the Modern Designer. Previously I would pass parameter values in the URL, which would populate a drop-down field. The drop-down field is based on a lookup. This worked fine in Classic, but I am finding that the Modern Designer won't accept any values that aren't hard-coded choices in the drop-down. In other words, even if the value I'm passing is valid based on the lookup, it seems to not accept it.

Any solutions for this?