This may not be a bug in PR 1.2 as the thread title suggests. Since it is effecting a relatively few users (so far) might I suggest that you use this space to compare notes regarding what is commonly installed on the N900's of those that it does affect.

For instance early on I did experience short freezes and delays when the "animation" feature was enabled in OMWeather. I disabled it and haven't had a problem since.

Another program that was in the developer repo that allowed you to remove or change the order of status bar apps could be causing this as well. I can't recall the name because I uninstalled the sucker and never looked back.