How common is this that they would even care about it anyways? I've run Firefox exclusively for the last 2 decades and have never once run into a site that told me I needed to switch to Chromium for compatibility.
"On Google.com if you present a Vivaldi user agent and arrive via a redirect, the search text box will be misaligned
On Google Docs if you present a Vivaldi user agent you will receive a warning
On Facebook’s WhatsApp web interface if you present a Vivaldi user agent, you cannot enter the site and are advised to switch to one of our competitors
On Microsoft Teams (chat and collaboration website), presenting a Vivaldi user agent will stop you from being able to use the website
On Netflix, presenting a Vivaldi user agent results in a suggestion to install Silverlight to play videos… yes… really… Silverlight!"
Used Edge, went through completely.
Can't guarantee it was Firefox/browser issues. But this is not that uncommon an occurrence.
I suspect it is the bank who are at fault.
But on chrome it went through without a hitch.
For my full profile the login attempt with Firefox as a user agent apparently pushed it over the edge.
Switching banks is hard, because all of them suck, are underdocumented and a moving target.
The blessing is I can just reject it and it blocks all their videos from playing/downloading.
It’s non-Google sites where Firefox may not be as well supported as Chrome, IME.
It doesn't seem to affect everyone equally. Pretending to be Chrome sometimes helps - not too long ago someone found a piece of code that introduced seconds of busy delay for any non-Chrome user agent.