It's probably improved the past 8 years or so, but I remember Safari was particularly bad for bugs around DST and just dates in general back then, even when using valid input.

We ended up with a bunch of Safari specific workarounds that weren't necessary on Chrome (it was mostly a webview use case so Safari and Chrome were the two we cared about at the time)

Assumingly to me this was around the same time that Apple seemed to have DST problems more generally, such as their iOS alarm clock mishap https://www.theguardian.com/technology/blog/2010/nov/01/ipho...