Smoothing lines in AGOL feature class error

[BeLockwood]

I am trying to use the generalize (smooth) tool to smooth a triangle shaped line in a feature class and am getting the following error when I try to save my edits:

The feature class is stored on AGOL and pulled into Pro for feature creation and editing.

I believe that AGOL now supports true curves, but does AGOL not allow creation/editing of true curves? Here are my settings for the layer:

Thanks for your help in advance.