Understandable to have a solid midfield against a team that was going to park the bus? Even if you want to stand by that logic then still counting to play that way for 70 minutes, when you've been behind for the last 33, is frankly idiotic.
And just how the fu*k Bellarabi played the whole 90 minutes is beyond me. Such a pathetic performance, how many crosses of his even connected? Oh wait, there was one shot that was so sh*t it ended up being a cross for Havertz.
Pathetic from Bosz, he's being found out for being average like he eventually was with Dortmund. 3 matches without a win now.
Yeah. It's the first CL match, they lost their last game 4-0, I can totally see why he went with Baumgartlinger to get a sense of security and build confidence, especially since the first choice alternative - Demirbay - is out injured. Favre does this all the time as well, starting with Witsel + Weigl/Delaney, taking a risk averse approach, trying to build momentum and tire the opposition via possession, only introducing a more attacking CM later on if needed.
A lot of people will pick on Bosz's subs, but Bellarabi, while lacking end product, was probably still Leverkusen's best attacker today.
Amiri was terrible against Dortmund and didn't accomplish a whole lot when he was eventually brought on for Baumgartlinger either.
The most questionable thing perhaps was not bringing on Weiser, who offers a lot more in attack than Bender.
People are so happy to throw around "found out", but I think it's mostly a question of individual quality. At the moment they don't convert the chances/spaces that his football creates and they make costly mistakes at the back. The game against Dortmund for example was relatively even and decided by Leverkusen's players messing up their counters, while Dortmund didn't hesitate to punish Leverkusen's/Wendell's misplaced passes.
His football can be quite demanding on his players and at the moment they can't deliver consistently enough for it to work. Of course it's fair to ask whether he needs (and is able) to make adjustments to lower that kind of exposure (e.g. introducing Baumgartlinger), but I wouldn't say he's been found out.
It's just the nature of such an approach that in the end you have to rely on individual quality. Even Klopp and Guardiola had some defensive issues, before they spent hundreds of millions on their defense.