I know this probably might not help a lot of people reading this thread but if you are rooted you can download an app called Auto Killer Memory Optimizer and change the settings in there. A dev or someone who has more knowledge than me (x99percent on XDA forums) says that the memory settings by HTC were too aggressive this update and when the phone detects too much memory is being used it will kill off Sense. You can set the numbers to 8, 12, 16, 24, 28, 32 which are the numbers Cyanogenmod uses in their rom and it supposedly works well.
I am not having this issue except when I close Plants vs Zombies so I haven't worried about it much. I also only use minimal widgets which might be why I don't have issues. If you load up on widgets it probably uses quite a bit more memory. Try removing a bunch of widgets if you use a lot and see if the issue is resolved.
One other big problem I have had is my HTC email app will not allow me to delete hotmail messages. They keep coming back as new and giving me notifications. I cannot believe something like that got through testing.