Cremona cracking leaves

[AussieBonsai]

Hi all,
Regarding a Cremona retusa. New leaves and shoots look very healthy, however anything older develop cracks and splits in the leaf. It has been fertilised and shows good growth all over, but have this reoccuring problem. Any ideas? I've adjusted watering etc, which hasnt helped, and so presume its nutrient based, but discolouration isnt an issue etc

 

[sorce]

Looks just old, how long have you had it?

Seems they could've been damaged when wired and just showing up as they age out.

Sorce

 

[AussieBonsai]

The leaves are only a few weeks (4) old, and it seems to happen to them all as they hit that mark.

 

[AussieBonsai]

But yeah, could indeed be heavyhanded wiring

 

[AussieBonsai]

I'm still having the same issue. Hopefully the attached photo will show the progression from small marks which go onto envelope the leaves. I dont believe its linked to ferts, and i've adjusted the watering both up and down. Any thoughts?