With the addition of deepslate blobs up to Y=16, The fact that copper and coal previously could only generate above Y=0 meant that there was no need for deepslate copper or coal to generate in the world. However, with the addition of deepslate blobs, these generations can overlap causing problems with consistency, see attachments below.

To reproduce: go into a cave in any seed and mash through some deepslate blobs around y= 14 and you will quickly find regular copper or coal generating inside. The deepslate ores also seem to be generating inside tuff blobs (below Y=0) which is again inconsistent with the fact that ores in tuff should be stone encased ores.

Just as A side note, The tuff blobs don't seem to be generating at all above Y=0.