Safari freezes when rotated iPhone 4

If Im in portrait mode in Safari and I rotate my iphone 4 to landscape mode, Safari will occasionally freeze (about one time out of 5). To restore it, I have to quit Safari, then tap the icon to rerun it. Usually it wont start back up on the first retry - It boots to the Safari screen, but its blank and is frozen. I knock it down and try again and usually on the second or third try it runs OK again
This freeze occurs intermittently and I cant recreate it. It started a few weeks ago. I thought that installation of 4.3 would help, but its still there.
Im assuming that since it has persisted through a firmware change (upgrade to 4.3), its not going to be helped by a restore, but perhaps Im wrong. If Safari wasnt a built in program, Id uninstall and reinstall a fresh copy - any way to do that? Since it glitches when rotated, I also wonder if its somehow hardware related to that rotation sensor.
Any thoughts would be appreciated. - Frank
Imac Mac OS X (10.5.4)