Looking at it my first thought was you'd set fire to it
On closer inspection I think I can see black aphids on the stem, not sure as my eyesights not great and the zoom isn't working. Hopefully someone else can see them better and help I'd the problem.
Oh my goodness I didn't realise Aphids attacked Acer! What's the solutio.....
If it is aphids dilute fairy up liquid and spray the entire plant. Make sure you do under the leaves as well as on top.
I can see the aphids too. But did it get cold as well?
Are they susceptible to wind burn because that's what it looks like to me?
I think it could be leaf scorch. Acers do not like windy situations.
Don't trust my eyes Paul, a proper Mrs Magoo.
When I find aphids on a plant I squish em but you can also blast them off with a spray of the hose.
No idea about the black crispy looking leaves though, sorry.
I will follow all the advic. Many thanks
Wind damage for me too.......this is why I grow mine here.