I've been having issues with polygons getting deleted and re-created in this layer, and also with polygons not merging the way I would expect. I thought I had everything fixed-- my topology check comes back clean (no gaps or overlaps) and when I fill the layer with a solid color there are no gaps-- but now my layers are behaving very strangely, and I'm worried I might not have fixed everything and I don't know what sanity check to use aside from my topology.
I merged it:
but sometimes when I zoom out, it looks like it is still in 2 pieces.
When I export it to a KML file and open it in Google Earth, it still seems to be in 2 pieces:
I feel like I'm pretty experienced with ArcMap but I have no idea where to start with trying to fix this!
I am using ArcGIS 10.6.1 on Windows 7.