Anyone else have a problem with the Table of Contents jumping to the top when clicking a layer on or off? It is super annoying when I have a long list of layers and when I click on one to display it my Table of Contents jumps to the top. Then I have to scroll back up or down to find the layer I was trying to work with.
Yes, I have seen the same issue, and it is still present in ArcGIS Pro 2.6. Like you, I have a very long TOC with many layers, and it is indeed a nuisance when it jumps back to the top of the TOC.
It doesn't always happen though, and I have the feeling it is related to Pro finishing some "refresh" task to UI or TOC in the background.
Once it has happened, and I scroll back down, I can click multiple layers on/of without the TOC jumping back to the top.