Josh, I too was having this issue but when setting up attribute rules. In my case, I was setting up rules on a point feature Bridge and the rule calculates a rotation angle that is parallel to the intersecting road. For whatever reason, I couldn't get the attribute rule to validate. Then I tried intersecting with the County Boundary, DOT District, and DOT Region and had the same issue. Then I started looking at my bridge data and it turns out the first two records didn't have geometry. They had attributes but didn't have a geometry. When I deleted them and applied my rules the rules validated.
Are you editing filed that have attribute rules applied? (I would not edit the attribute columns that have attribute rules applied)
Are the existing features you are trying to edit have geometry? (I'm assuming they do but don't want to leave anything to chance.)
I would open a support ticket if these items don't help you.
Eric J. Rodenberg | Solution Engineer Transportation Practice
Esri | 7775 Walton Pkwy, Suite 270 | New Albany, Ohio 43054-8202 | USA
T 614-933-8698, ext. 5503 | erodenberg@esri.com | esri.com