Issues with the Membership Plugin

My client's site has the Membership Premium plugin, version Version 3.4.6.1
She was getting an error which was making it so that when users signed up for a particular level (the other levels worked fine apparently) they weren't being assigned properly and had to be done manually. I was told via a support chat session that it was a known issue and would fixed with an update of the plugin.

I updated the plugin to the latest version, but all of a sudden when users tried to sign up, they were getting redirect errors and it wasn't bringing them to paypal. I reverted the site back to the original version and the redirects fixed themselves but now we're still stuck with the new members not being assigned their access and subscription levels automatically.

Thanks for your help, really need to get to the bottom of this.