When publishing to AGOL from Pro, publishing is adding an extra giant polygon overlapping the data.

[RLS]

I am publishing to AGOL from Pro. The data shows up correct in Pro and in the thumbnail view of the published content. But when it's opened in map viewer - it adds a giant polygon. The polygon goes away if I zoom in. I've tried publishing in a new project with new data and the same thing happened.

How it looks in Pro: 

How it looks in AGOL: 

Zooming in resolves it: 

[Laura]

Sounds like it is just lagging or something. Have you cleared all browser cache?

[RhettZufelt]

Sometimes geometry errors in the featureclass can produce this.  You could try the check/repair geometry tool in Pro on a copy, publish and see if the issue goes away?

R_