Which plugin do you think is causing the problems.
Hard to say. I’ve used these in your list without any problems:
ContactForm7
EWW Impage Optimizer
Limit Login Attempts
Redirection
Simple Image Sizes
That’s not to say that any one of those in combination with one or more of the others you’re using couldn’t cause a problem, but I’d be a bit surprised if that were the case. I’d be inclined to start by disabling these:
CloudFlare
CometCache
I don’t think they’re causing the issue but, if they aren’t active, then you know you’re working with only one instance of the site. If that doesn’t do it then the only real way to find out is to disable all your plugins and see if the problem is resolved, the idea being to get to a known good state where the theme operates correctly. Then start enabling the plugins one at a time until you find the one (probably only one but it could be more, or some combination) that causes the issue.
If your host gives you cPanel access, or you’re comfortable using FTP, you might consider setting up a subdomain, copy your existing v2.2.3 site (using a plugin like Duplicator) then restore it to the subdomain, upgrade that copy to the new version and do your testing there.