"Players can start delving from act 4 onwards.." is a lie???

OMG after my last post I went back into the game and went to the Toxic Conduits and found Sulphite there for the first time. LOL! I truly believe someone made that happen so I wouldn't bad mouth then for their crappy delve mechanics.
Since I'm talking about it again, lets compare it to Heists. When I recently discovered Heists I was like "Wow, this is new and different. And quite challenging. Could be fun". Then I was disappointed to find out I couldn't do any more until I got lucky enough to find some contracts. But, I have. I have found contracts and quite a few markers.
I think they should just move the mine out of the current act and put it near the end since they don't want us delving that early.

You can buy contracts from Wakano in the rogue harbor. They only scale up to level 67, though (which is the opposite problem you expressed about delve).

I have one more comment. After finally finding a little sulphite as mentioned above, I went and did a little delving. After clearing the first spot, the game told me to speak to Niko. When I did, he said the same things he did in the introductory mission and I got a game message that I had completed the mission of delving for the first time. Which was not true, again, I had done it before in the introductory/tutorial mission.
So, I wonder if part of the problem is possibly with the game not properly flagging the fact that you have met Niko and can Delve now.