2022 Triton random shifting issue

I have a fairly new to me 2022 Triton with an automatic. This is the same Aisin AC60 found in the Hilux and Dmax, supposedly a strong and reliable transmission. My Triton has only done 71,000km and up until now has shifted perfectly.

This morning on the way to work, the first four shifts from 1st to 2nd were very harsh, then it was fine after that (after about 2 mins). On the way home it was perfect again.

Any transmission experts have any ideas what this could be?