Ghost mods just aren't dropping.
It's an issue that is plaguing a lot of new/returning players such as myself. I've seen various myths and conditions floating around online - I've fulfilled them all but still nothing has dropped. I've clocked a total of 77 hours since returning this season and have yet to see a [b]single[/b] ghost mod drop.
It's only start to become a real problem now as I'm unable to reliably farm high stat gear, and my progression through content has been halted until this issue is resolved. To be honest there's no need to lock ghost mods behind random drops in the first place.
A less intrusive annoyance of this situation is that I have been stuck with +10% exp instead of +12% - this is way less harmful to the game, the main thing that needs fixing ASAP are the armourer mods.
EDIT: Didn't even realise it was an issue but apparently weapon mods exist too. It seems that we new/returning players also have access to a whopping zero weapon mods, adding to the frustration.