thumbnail rendering just 6mb?

I'm getting

Thread 5: EXC_RESOURCE (RESOURCE_TYPE_MEMORY: high watermark memory limit exceeded) (limit=6 MB)

My thumbnails do render (and they require more than 6mb to do so), so I wonder about the behavior here. Does the OS try to render thumbnails with a very low memory limit and then retry if that fails?

thumbnail rendering just 6mb?
 
 
Q