Are you using ArcMap Desktop or ArcGIS Pro? You keep saying ArcMap, but posted in the ArcGIS Pro content group. I will assume you are using ArcMap Desktop for the moment, since I am more familiar with troubleshooting that application than I am with ArcGIS Pro.
Normally, you should first assume that strange behaviors are directly created by the specific map document you are working with. This is especially true if you have been using this map document over the course of several ArcMap version upgrades. Have you tried opening a brand new map and adding data to it directly from disk? If your data displays normally in the new map while doing activities you have describe then your saved map is either configured wrong or corrupt. If this is ArcMap you should try MXD Doctor. If that doesn't work, you should then try copying the layers of your corrupt map and pasting them into a brand new map. If that solves your problem kill the original map and start over with the fresh one. If the problem starts occurring as a result of the copy paste only, then the problem is definitely in the way the layers are configured or with the data. You may need to rebuild the map completely from scratch and only reference the original map during the rebuild process to replicate it without copy pasting anything.
If you rebuild from scratch you may discover several problems in your configuration. Configuration problems could include invalid label or definition query expressions, possibly caused by schema changes in your source data, or corrupted data. You may need to run the Repair Geometry tool on your edit feature classes.
If the problem occurs when you start with a completely new map and directly add data to it from disk, your default map template may be corrupt and should be deleted and regenerated. If regenerating the map template fails to resolve the problem, then your software install may be corrupt.
This does not exhaust all of the possible causes of your problem, but this is the normal order of the things I try to troubleshoot this kind of problem.