I have never tried to actually use tables in Scrivener. But my understanding is that tables, similar to lists, are finicky and flakey and will not behave or submit to even routine editing as expected. That includes issues with formatting and layout, and this is apparently common to both the Mac and the Windows/Qt versions, though perhaps especially the latter. This recently active thread can give you more info, as can many others that a search can turn up.
In the mean time, you can try posting a screen shot of the problem you are having.
Actually, using screen shots of lists and tables that were created in other programs, and pasting them into Scrivener, is a commonly recommended solution to the problem.