I'm going to take a stab (pun intended) at what's about to happen. I'll mark it as spoiler stuff if you don't want to see it.Warning: Spoiler! (Click to show)
There's now confusion on which is the real Marta Del Sol. I think the one JR met when he went to see Carlos is the the true phony. The genuine article is in Texas playing all the guys (Bobby, Christopher, John Ross and even JR) against each other. She's sowing dissension and confusion between family members in order for the sale of Southfork to the Conservacy to happen.
The contract will look legitimate and will be vetted, but will have a clause buried deep within it allowing, after time has passed once the sale goes final - say 12 to 18 months, for 'exploratory' drilling on the property. And they (the new ownership) pretty much know where John Ross was drilling, so they know where to start. And with the Ewings kicked off the property, there will be little anyone can do.
And who's the man behind the curtain, pulling all the strings? Carlos Del Sol himself. Some humanitarian he turns out to be.
What do you want? It's Dallas. Everyone backstabs everyone else. Maybe except Bobby, but if he's dying of cancer, that 'high and mighty' attitude may go away too.