Spot remover leaves artefacts on image

[richardb1605217]

Hi,

Ive just started noticing that Camera RAW is leaving black blocks on my image where I've used the spot removal tool (see pic) 

This is a DNG file from the Magic Lantern hacked 5D3

Has anyone seen this before? It's only started doing iut since the last update.

Thanks in advance

Black squares for spot removal?