I am running ArcGIS Pro 2.3 on a Windows 10 Desktop.
I can not edit an existing polyline that is drawn in GIS, though I can still create a new feature. When I select a line and to edit the vertices I'm allowed to move and edit the line as I wish but, when I double click to finish the command the line reverts to it's original place.
My workaround is creating a new feature and copying the attributes but the data I am working with is rather large and this can become tedious.
I did not have any problems until I opened the program this morning.