The OPI is as often not called as called. Frankly more often not called. Still, it can be called at any time, so the WR always needs to be careful.
Mac to me is a great QB when it comes to executing the plan, hitting the pass, and finding the obvious target when things break down. But he isn't really doing much to create himself. I'd like to see more pump fakes, more eye/head movement to manipulate the D. I'd like to see him calling things at the line and signaling his WRs when things break down. Basically, he has all the physical tools to be a very very good QB. But mentally he isn't adding those things to take the next steps. He doesn't need to be Brady or Manning mentally, but i'd like to see more than we're seeing.
The issue is that it's VERY hard to worry about doing that at the same time while also reading the field and hitting throws. There is a reason guys who can do both at once at a high level are extremely rare. It's doing math while reading a book at the same time. But like I said, he doesn't need to do both at an extreme high level. Just adding a little of those things here or there would make him jump a few spots in the current QB ranks. To me, right now Mac is basically a lot like Carr. Which is fine and he will be at Carr's level with a little more seasoning, but if he wants to take the next step he really needs to add those other things.