I agree, It is very possible the tests being administered are not accurate. IF the Rams had 29 people on their team test positive and truly had the virus then it would be IMPOSSIBLE for any team they played in the last few weeks to also not have an outbreak.
If anything I would expect to see the Cards get struck with it as they just played the Rams Monday and between Tuesday and Friday had 25 more players test positive including Higbee who had just been tested and found to have had a false positive.
Whatever batch of test kits they are using needs to be sent in to be analyzed for contamination or improper administration processes, same with the Browns.
As with anything that is highly contagious if 1 person has it and is in close contact with others. Then others will catch it. Maybe not all due to anti bodies. But there would certainly not be 29 on one team and 2 on the team they just played. That's unrealistic.