Werid Timezone Behaviour in Vivaldi + Chrome with MacOS 14

extrobe

I, and others, are experiencing a weird set of behaviours since upgrading to MacOS 14, but I think they're related, and have Chromium-based browsers in common.

In short, I think there's an incompatibility between the timezone Vivaldi / apps using Vivaldi are receiving from the system vs what it's expecting, which is leading to some issues.

MacOS version: 14.0
Vivaldi Version: 6.2.3105.54

The easiest way to show this issue is to look at the time in Vivaldi vs my System time. You can see they're an hour different.

And here's how it shows in my MacOS systems.

Note: We've just moved into DST here in Sydney, so timezone went from AEST to AEDT. But although this has made the issue more obvious, I think here's something more to it, as we're having issues with two different web-based platforms...

Slack:
In Slack, all messages are offset to the wrong time. If someone posts a message at 09:00, it shows me they posted it at 08:00.
This is the same in the Desktop app, and also when using it directly in the browser.

(When opened in Safari, it's fine)

In Slack, if I check the Language & Region settings, it thinks I'm in Brisbane (UTC+10).

And if manually set it to Sydney, it's still not showing the correct time (we're UTC+11)

Snowflake Web UI

This is where I first saw an issue. In certain screens, such as looking at logs/history, we get this error message...

.

I already have a support ticket open with Snowflake, and have shared HAR files with them.

--

I know this feels like a Snowflake / Slack problem, but they have some common threads that makes me think it's a Vivaldi problem (or more specifically, a Chromium problem);

It's all time / timezone related
In all cases, these issues show in Vivaldi and Chrome. But Safari is fine