I am having this same problem. I am teaching an Intro to GIS course using ArcGIS Pro in the classroom for the first time. I do not get this error message when using the Explore tool to click on a feature on my home computer, but it is happening on my campus computer. This is going to screw up my demonstration in class tonight...
I am using data from the Esripress book "Getting to Know ArcGIS Pro 2.6".