[lbriner]

I'm British but I always understood it as the second meaning. e.g. "We were going to consider XYZ but now it's a moot point because the project is cancelled."

[mrob]

I've heard it used that way in the UK too, but the first meaning is traditional. Wiktionary has some examples:

https://en.wiktionary.org/wiki/moot

I expect the US meaning will eventually become standard everywhere.

[dofm]

It sort of means both simultaneously, doesn't it (we could discuss it but it's inconsequential), but we do tend to use it in that formulation most.