This sounds plausible. Beyond explicit user gestures in the Connections pane, most of the UI updates are driven by R itself (e.g. by the driver or by the driver interface package).
There's a couple things we can do to get more information.
The next time the hang occurs, try looking at Help -> Diagnostics -> Request Log. You'll be presented with a graph of some of the different operations RStudio has been doing. If you see a "long" bar (other than 'get_events'), that may be associated with the slowness you're seeing.
You could also try generating an R profile. Within R, execute:
utils::Rprof("~/rstudio-trace.Rprof")
to start the profiler. Then, work with the IDE until the next bit of slowness occurs. When that happens, you can stop the profiler with:
utils::Rprof(NULL)
Then, share the output of:
utils::summaryRprof("~/rstudio-trace.Rprof")
and that may point us towards the function(s) being invoked that are taking a long time to complete.