The only thing I can find online is that MAYBE there's a loophole where you can't call intentional grounding because the pass was caught. However the rule on the NFL operations website states that "a realistic chance of completion is defined as a pass that is thrown in the direction of and lands in the vicinity of an originally eligible receiver". The OL was clearly ineligible so there is no realistic chance of completion.
At the time, I thought maybe there was some overlap rule or something where the illegal touch negates grounding. After reading the rules, they should have thrown 2 flags, one for grounding and one for illegal touching. There's no negation there. It makes me so angry with how we've been penalized. If I had access to the game replays, I would go back to every penalty and see how many of them were soft/phantom and which team they were called for. Would be a great YouTube video and help us see if it's been as bad as we think or if we're biased.