Equal Symbol Appended to URL

[Bestrafung]

For some reason when some links are clicked, especially from external sites or search results, an equal symbol will be appended to the URL. If you do a google search for our site about 90% of the links have the equal symbol appended and are broken.

Before we started using an SEO plugin this would cause the visitor to be redirected to the main page and contributed to a large bounce rate. Now after the SEO plugin it gives a page not found error. I have removed the plugin and am no longer using it. I need to redirect it's broken URLs back to the vb default.

I've tried several rewrite and redirect rules in .htaccess with no luck. I need to be able to remove the equal symbol from the end of the URL, any URL. I saw someone else posted this exact issue in 2015 and I checked their site and they still have the issue. I'd really appreciate any assistance with this.

Example Bad URL:

https://subdomain.example.com/content/?123-Article-Title=