"Invalid Variant Operation" error when creating Sales Order detail lines

The error popup occurs after you create a new line, then select the Reference ID, and then go to enter a quantity against the line.The error message that pops up offers an option to Submit to Support or Close. You may do either, and once you have done so, the error popup will be dismissed, and you can continue with entering the quantity against the line.

We are unable to consistently reproduce this error in our internal testing.  If you are getting this error consistently, we would like you to submit a support ticket with the steps taken to 

 to reproduce this error, and example of the item ID(s) involved, and a screenshot of the SO Detail screen at the time of the error.   Our support team may ask you to send us your database so we can explore the root cause of this issue and get a programming fix.