Ok so this is a strange one. Ever since I installed and activated this plugin, I have one user only who is experiencing a timeout on some pages. There may be more users, but she's the only one who has approached me.
So this is the page that she can access fine, but when she clicks on any category bar 'bundles', it takes forever to load, and then eventually loads a 503 page.
I've switched to her account and I can replicate the issue. I've tested other users randomly and cannot replicate the issue. I also don't experience the problem. When this user is logged out, it works fine.
I've deactivated the plugin and the other categories load fine for her when logged in, so it's definitely the plugin. My hosting provider is looking into it, but I think I should reach out to you too; it's very odd.