Site with Mobile Template kindly double check at your end!

Hello SI Team

Can you kindly check that my site is loading correctly on a mobile device?
https://www.finalbug.net/
I have tried on several and get all kinds of weird variations.
eg

Site taking up half the screen
Drop down menus appearing and not going away etc..
Filter buttons at top instead of bottom

I have the mobile template (latest version) installed:

https://stackideas.com/apps/item/3361-mobile-web-template

And I am guessing that I am missing something really simple...

So much has changed in the last couple of months

kindly advise

Paul