In the last 2 games the Bengals have given up 5 TD drives... on 4 of them they had the opponent in 3rd and long, sometimes more than once.
Vs. Houston- The Texans only TD drive, they converted a 3rd and 8, and a 3rd and 13 before scoring.
1st TD drive- Bengals had them in a 3rd and 8, and also a 3rd and 16 and couldn't get off field.
2nd TD drive- Bengals had them in a 3rd and 7, which Cards converted before long TD throw.
4th TD drive- Bengals had them in a 3rd and 14, tried a blitz, and Dre couldn't make a tackle. Led to TD.
Bengals have had plenty of chances to get off the field and prevent scores, but either the pass rush has not gotten there or the coverage has not been there... but to survive in the playoffs they have to do a better job.
It's a good thing to watch for the next couple of games in how well they do on 3rd and long, because at times teams will convert on you, but it should not be happening this often.