Just ran into this and see nothing listed about it elsewhere. I have a detail table set as a popup in the grid and also to show on the View and Edit pages. When I first load the List page, the form pops up unformatted.
On the View or Edit page it shows up with formatting, which it will keep on the List page popup until the List page is refreshed.
Not a big deal, but I'd prefer having the formatted version all of the time. Any ideas?