You can always learn something new about the NFL rule book.

When the Bears played the Vikings on Sunday, Minnesota receiver Jordan Addison appeared as if he might have stepped out of bounds amid a 69-yard reception in the third quarter.

Bears head coach Matt Eberflus challenged the ruling on the field that Addison stayed inbounds, but it turned out that a Soldier Field camera that shoots the boundary of the sidelines was not able to be used.

“This is the boundary cam, and if a coach challenges you cannot use the boundary cam. There’s not boundary cams in every stadium so there’s a question of equity, whether some stadiums and some don’t have it. So when a coach challenges, you can’t [use it],” Fox Sports officiating expert Mike Pereira said.

The rule only got stranger from there.

“On a regular review situation like a scoring play they can [use the boundary camera], but not on a coach’s challenge,” Pereira said.

It seems very bizarre that boundary cams would be allowed to be used for one element of reviews but not another.

ProFootballTalk reported Sunday that the NFL is introducing boundary cams to stadiums on a rolling basis.

The variance of cameras between various NFL stadiums and broadcast partners has come up a couple of times this season.

In October, Falcons tight end Kyle Pitts had a controversial play against the Buccaneers where his catch-and-run was ruled a touchdown and it could not be determined if he fumbled before crossing the plane of the goal line because there was no pylon camera.

“I don’t understand why this is such a problem,” legendary former Patriots head coach Bill Belichick mused in the aftermath.

“A camera could easily be mounted on the sideline just like they have in tennis — on the end lines and the sidelines. Or just build a stand and put it on there. I can’t imagine money is a problem. The NFL has plenty of money. They can have a car wash and raise money if money is a problem.”

Although the Bears took the game to overtime, the Vikings prevailed, 30-27.