odd leaf change in weeping maple

I am hoping someone may be able to help me identify what is the problem with my weeping maple.
I have had this maple for at least 20 years in a pot.Last time I re potted it, about 18 months ago, I half submerged the pot into the ground on top of 2 bricks . The ground soil is sand so drainage is good.
I have recently noticed that the leaf shape has changed considerably and mostly on the ends of the branches. The inner part of each lobe has reduced to the central vein and the serrated tips have elongated to 2cm at its widest.
It is mid autumn here and the tree otherwise looks normal for this time of the year.
Hopefully I will be able to post some photos with this post( haven't posted photos before)
I would be most grateful if someone would be able to identify the problem. Thanks.

 

That second pic looks as though it has been eaten?

 

Looks to me more like it might have caught a bit of herbicide drift - have you beem spraying weedkiller nearby at all?

 

Probably genetic.

 

Quite a bit of variation is normal, and often the second (or third) flush of leaves can be shaped differently than the first.