A couple of things. HEM can run slow at times where your hud stats don't update for five or so hands, I've seen it run idle for like 20 hands in some cases and then all of a sudden update the hud. The 20 hands happens rarely, the 5 hands happens a lot, you can also have a filter on where your hud is only updating every five hands and you are just now noticing it. That filter is customizable and can be set for any number you want. So that could be causing the problem. A while back, if you had your hud updating every hand, it would cause a bunch of lag, so a lot of people had their huds set to update every five hands, this took care of the lag problem. Look in your configure HUD stats. See what the settings are for updating the hud. I use PT3 now, so I don't remember where all these settings are located. But if you want to do a teamviewer session with me, I will be able to figure it out when I see it.
You could also have a filter set showing only stats for the current blind level. That could also be causing your problem.
Third thing is, it could be the update, or the update turned the show stats for the current blind level filter on.