Yannick Hey, sorry for taking a bit to get back to you - I'd been limited to my iPad for a bit there.
I've tested that now and I got a highly similar (though technically different?) error in Safari 18.2 (20620.1.16.11.8);

(Please don't ask me how long it took me to figure out how to open a Console in Safari...)
I then tried to reproduce in Chrome 134.0.6998.89 and initial testing failed to reproduce the issue.
I then tried to reproduce in Firefox 136.0 and... lol, what?

198..?
I started looking at errors and they'd nothing to do with the website at all - it was complaining about Mozilla telemetry, containers, and... seemingly just about everything else that has ever existed. I couldn't be bothered trying to comb through all of that looking for related errors, especially after being able to reproduce in Safari but not Chrome.