I can see that this has now been picked up by our support team.
I believe that when the extract was converted it could've become corrupted.
I had this slow issue in 10.5.2 as well, but once I upgraded to 10.5.3 the issue was cleared. This appears to have been a problem between Hyper and the parameters that I had created. I tend to run nearly everything from parameters rather than quick filters.
Tim, thanks for the reply. That’s useful. I too use Parameters everywhere, so hopefully the upgrade will fix my problems.