These appear to be when the "prospecting mining perk" is picked.
The 'extra' ore has the metadata tag "Cannot be placed".
This means the ores cannot be processed in machines and just clog it up, sit there until manually removed.
Here are some other otherwise supporters of the mod who're uninstalling to get around the issue at current rather than report:
https://www.reddit.com/r/Minecraft/comments/8z1dtm/bug_with_mined_orecannot_be_placed/