Adam:
boborg,
When you think this issue happens, please clear your browser cache. Because you are loading the same page after editing, you may load the page from IE 7 cache.
I did try clearing IE 7 cache already, sadly without success. If I check the entry in the database I can see that the update is not saved correctly so it cannot be something in cache only.
I've just downgraded to Cuteedit 5.3 and I have no problems now in IE7 so I'll stay at 5.3 for now.