I've seen the first issue you mentioned on my system too although strangely it seems to be working at the moment. I've found at times that onlly the 'update every xx hours' scheduler actually works. I'm afraid I don't have time to look any deeper into it at the moment.
I get this issue too. I'd be happy to take a look at the code to see if I can replicate and fix the issue under my environment. Is the plugin code that hosts the scheduling feature publicly available?