What’s wrong with my Beech tree sapling?

Hi all! Total newbie to gardening here 😊

What’s happening to my Beech tree? It was growing well until about a week or two ago when these yellow/brown spots started showing up.

I had the sapling in a large planter outside in the QLD sun so i thought maybe it was too much sun, so i popped it into a smaller/temporary pot to move it under the patio shade. I’ve sprinkled some fertiliser on it & haven’t let it get water logged (lots of rain lately) but it doesn’t seem to be getting better.

Help!