Best answer by Mw2870
These both sound like technical issues on a traditional meter (non-smart) usage graph. We can get this raised to our Tech team to look into if you send a message to the team on Facebook of Twitter with your account number, full name and Do or, email them at firstname.lastname@example.org.
Just as a side note, OVO are currently slowly porting smart users over their new online experience, with a view that eventually everyone will be on the new system. This uses a different graph, so hopefully this bug isn't present any more.