Cannot complete Niko's Fuel or Niko's Mine

Faced a problem, the quest Niko's one collecting sulfite is cannot be completed!

I already collect thousands of sulfites, but the quest is still active in the 4th Act of collecting 5 sulfites!

Every time when I finish the map, a notice “talk to Niko” pops up in the hideout, but this does not lead to anything, and it shatters me very much!

Help me please!

I'm having the same issue. Quest keeps popping up repeatedly no matter what zone I'm in and I can't get rid of it.

Same problem.

same here. very annoying.

And another victim here, cant believe this bug still exists..