Confusion with 24-bit/truecolor on Windows

[SquidDev]

What Operating System(s) are you running on?

Windows

Which Wayland compositor or X11 Window manager(s) are you using?

No response

WezTerm version

wezterm 20240203-110809-5046fc22

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I've been running into some odd issues when trying to use 24-bit colour escape sequences in Wezterm on Windows. According to the documentation, the correct syntax uses colons (\x1b[48:2::R:G:Bm) rather than semicolons.

However, when trying this on the Windows version of Wezterm, this does not appear to work, but the semicolon form does! This occurs both within WSL and Powershell:

Just as a sanity check, the colon form does work on Windows Terminal and on normal Linux WezTerm:

I'm very confused what's going on here. As far as I can tell, the result for the two formats should be identical, so wondering if there's something else in my setup interfering with this. Is there anything I can do to debug this on my end?