Run-time error when closing the Notes field

The following error intermittently shows up for some collectors when using the Close Form button to exit out of the Notes field:

I can't replicate this in my test version. Who all gets this, and does anyone know how to make it happen consistently?

• I get it whenever I enter something on the notes field and then exit it but do not have a WBC entered.--CMarks 07:23, 2017 November 1 (CDT)
• I get it whenever I close the notes field --Jvelasco 07:39, 2017 November 6 (CST)