I’m running Chrome on Linux, and only use Chrome for T212. I have no Chrome extensions.
I’m finding my sessions are consistently expiring dead on 30mins, whether that’s leaving the screen open, or being active within the T212 web environment. I tried manually refreshing every 10mins too, get the same experience at 30mins through.
Slightly stuck what to try next? I have firefox, however, this is used for normal browsing, and also had the same 30min experience)
Which flavour out of interest? I don’t often come across fellow Linux users in the wild!
I’m on mint with xfce4! (dell xps 9300 laptop, 2tb drive, 32gb ram), I’m half tempted to go full arch with a minimal window manager and become full nerdy with a beard
I’ve been there though minus the beard. I even ran DWM on Gentoo for years. It was peak optimisation but I spent so many hours compiling stuff! 
Nowadays, I also run Xfce but on Debian stable – which I swear is the most stable and reliable operating system known to man.
I tried debian in virtualbox, really liked it, although a lot of the things I needed wern’t in the repo, I’d be quite happy to go with it to be fair. I’m finding the mint updates are becoming a tad heavy for my liking, I really want a minimal system install, coming from 20+ years in the finance IT sector (back end infrastructure) I shudder at the complete and utter bloat we are getting nowadays, I have win7 in VB with office (as/when needed), aside from that, no way am I going back to win, been a linux user since 2020 - it just works!
The neckbeards at Debian have got a lot better in the past few years in terms allowing non-free software like wifi firmware etc. It’s essentially what you’re using now without the Mint-specific stuff.
The minimal ones like Arch, Void and Gentoo are great for control or if you want more up-to-date software. For me, the biggest benefit is being able to easily pick OpenRC or runit over systemd.
But you sacrifice stability to some degree with Arch etc and there’s an opportunity cost to how much more sysadmin you need to do.
Apologies for derailing the thread, hopefully someone at 212 can help with your issue.
@TUK, I’ve just messaged you - please check your inbox. 
A security feature, built for our own benefit.
Also, speaking of security, if I were you, I would never discuss platform specifics on any public forum.