Answer:

Here is an example where scrolling may appear to be stuck on the History page; the top line shows that Foxhound had been stopped for over three days as of 9:09:20 AM on September 4:

       9:09:20 AM  3d 17h 3m 43s  -- Foxhound stopped --
Aug 31 4:05:37 PM  3.1s           -- Foxhound stopped at --

If you try to scroll to an earlier sample by one "Day »" Foxhound won't do anything because there were no samples recorded on September 3.

Try clicking on a different scroll amount (e.g., "1 sample »") or click on one of the sample lines before the gap (e.g., the "Aug 31 4:05:37 PM" line).