Attribute Rule not saving in ArcGIS Pro when the feature class is in WGS 1984 Web Mercator (auxiliary sphere)

[AbiDhakal]

Hello GIS friends,

I'm trying to save an Attribute Rule in a polygon feature class with WGS 1984 Web Mercator (auxiliary sphere) projection and it is not saving. However, when I put the same Attribute Rule for a feature class in NAD 1983 UTM Zone 16N projection it gets saved. 

This is what I'm putting. round(Area($feature, 'acres'),1)

Thank you for your help.
Abi

[AlfredBaldenweck]

Weird. Does it change if you use AreaGeoDetic() instead?

[AbiDhakal]

@AlfredBaldenweck - When I put
 
AreaGeodetic(Geometry($feature), 'acres')

for a feature class in WGS 1984 Web Mercator (auxiliary sphere) projection it does not save. It verifies the expression to be correct, but it does not save. Also, when I put that expression for a feature class in NAD 1983 UTM Zone 16N projection it verifies it wrong.

[AlfredBaldenweck]

If by verifies it wrong, you mean it returns a different value, that's expected. Area and Area Geodetic measure differently.

Testing it out myself, I also get that error for the NAD83, so that's fine.

I'm testing in a file geodatabase in Pro 3.1.3, and it's working for me

Make sure you have the following if it's just a problem literally saving the rule:

1. Rule Name
2. Description
3. Field
4. Expression
5. Triggers

I frequently can't save because I forget the description.

[AbiDhakal]

I have these and I'm still not able to save.

1. Rule Name (Get Area)
2. Description (Get area)
3. Field (GISAcres)
4. Expression: AreaGeodetic(Geometry($feature), 'acres')
5. Triggers (Insert, Update)

Thank you for trying to help me.

[AlfredBaldenweck · Accepted solution]

If it's red, mouse over it to see what the error is.

Ohhhh the other thing that I forgot: The feature class must have GlobalIDs enabled. That's bitten me several times.

[AbiDhakal]

And the bite took a chunk out of me; it's been very painful so hopefully I will not forget this one. Thank you! That did it!