Selecting a centerline blocks labeling

[AndrewVitale3]

I recently noticed that choosing a centerline via the R&H toolbar seems to block labeling in my map document using Esri Roads and Highways on ArcMap 10.5.1. A little bit of blocking is understandable, but it seems like the entire geographic extent of the centerline is stripped of labels. Here's a visual (Centerline is selected in first screenshot, labels still present. Centerline chosen in second screen shot, labels obfuscated):

This behavior is present with both the Maplex and Standard label engines. Has anyone else noticed this?

More importantly, has anyone found a way to change this behavior? It's disruptive while editing/creating long routes.