Css on Samsung TV browser (Tizen)

[Atro12]

Im using Openspeedtest for lan tests and on my samsung tv with the integrated browser (tizen) the website elements are all stacked up making it unusable, i've been able to replicate it on my desktop browser by disabling css, so the problem has to be with the css on tizen browser.
On samsung mobile the website works fine (i think because that version of samsung internet is based on chromium?)

EDIT: the site on tv looks like this (this is on pc without css because its easier to screenshot)
https://i.imgur.com/51DPFR1.png

[openspeedtest]

Try Incognito/private window & clear browser cache.

[Atro12]

Try Incognito/private window & clear browser cache.

The browser is very limited and doesnt have an incognito mode, i tried deleting cache but nothing changed.
Here some additional infos:
This is the link i get after the speedtest:

https://openspeedtest.com/results/show?&d=84.405&u=65.383&p=7&j=3.3&dd=139.702&ud=92.063&ua=Mozilla5.0+(SMART-TV;+Linux;+Tizen+4.0)+AppleWebKit537.36+(KHTML,+like+Gecko)+SamsungBrowser2.1+Chrome56.0.2924.0+TV+Safari537.36

Note that this website is displayed correctly except for the section with the results that are all tangled up (those above the email,facebook,twitter share buttons) in the same way as the speedtest page in the screenshot i posted in my original message.

Edit: The precise browser name is TizenBrowser 2.1.3.0721073

I've also found this page with all the css supported features
My TV has Tizen 4.0 (2018) in case it could help narrow down what section of the css is causing the issue

https://developer.samsung.com/smarttv/develop/specifications/web-engine-specifications.html