One of our users noticed that saving a list (called, say, X) as a template seemed to complete successfully, but when she attempted to create another list, this list (X) didn't appear as one of the available templates.
There are several of her templates in the list, but it turned out that all of them were saved before the date we disabled property promotion on the relevant site (which we did for several sound reasons).
I can reproduce the problem on command, this way:
With SPWeb.ParserEnabled=true, saving a list as a template works as expected.
With SPWeb.ParserEnabled=false, saving a list as a template produces a .stp file WITHOUT metadata (because property promotion didn't take place). Although Sharepoint claims that the template was created successfully, it doesn't appear on the list of available templates and hence can't actually be used.
I've built a workaround via an event receiver, but I'd rather see this fixed.
I'd report this as a bug, but there doesn't seem to be any way to do that on Microsoft Connect, and I won't spend money to report it via PSS.