Sounds like it could be flooding the carto. I had this problem with the included cartos, but have not with any that have been punched or dotted (in my Liquinator or other tanks), so my guess is it's a result of the slot being too big. It could also be that the central air tube is collapsing when you draw on it, this would cause the issues you mention.
Either way, trying another carto is the only solution I can suggest at the moment. I only got a couple of fills before encountering the same problem when using the cartos included with my liquinator, but have not had this issue with others I punched myself.