I'm also having a problem with the layout in the gym, but only in the gym selection side panel. It looks really 'off':
By nix 
* Page is much less responsive. There is a 1-2 sec pause after every click of "train" before it can be clicked again.
Have included screenshot:
This looks like what happens to me when travelling or going to the gym; the page looks like that (complete with bullet lists for the items - ie. captcha, recaptcha, or the gyms in the side panel) but quickly fixes within a second and loads the rest of the page.
Your screenshot looks like it doesn't load the entire page and gets 'stuck.' Maybe you have lag as well as some other issue?
As for why I use mobile version, it's because the in-site chat feature is bugged for me. Has been since the day it came out. If someone messages me it comes up as per normal. But forever after that I cant get rid of the chat window. If I close/minimise it, it just reappears when I navigate to another page. I'm not sure why/how they end up disappearing but sometimes they stay up for weeks/months. I've brought it up before and staff have got rid of a specific persistent chat window, but as soon as someone else send me a message it just happens all over again. Therefore I gave up on full torn.
Hope this answers your questions and you can enjoy playing Torn.
I've made my own work around by applying a simple userjs to torn. It changes me to full torn mode only for the gym page, then back to mobile again for all other pages. Here is the code if anyone else wants it.