That's a crazy strategy from them on the 3rd game. Mid troll and carry Anti-Mage.
It's not a crazy strategy because Troll and AM are a common picks in pub games, maybe the Troll pick was unusual but AM as a carry isn't that crazy, I think that it is actually a good one because Troll can tank the hits and as a Midlaner can help in terms of objectives which AM alone can't do in a pro DOTA scene.
The mistake I do only saw on Hellbear is that they don't have much hold and they do let AM farm until late game which its really hard to stop when its already almost on lock in item.
If we do observe on how Hellbear behaves between clash then you can see that they aren't synchronize and doesn't really much react varying on the situation unlike OG.
You can really see that each player does know on when to get in and get out in a certain clash.
[DOTA 2 + CS:GO, Wednesday, April 28th]
PSG.LGD vs Invictus Gaming: Invictus Gaming ML @ 1.99
Really hard to tell between these two teams since both are good but I would be sticking with IG.