It can sometimes happen that Munich loses some points somewhere. I also don't rule out that they are going to lose some more matches. However, they will become champions at the end of the season. The rest is not constant enough to join.
Bayern Munich is a very strong team. But they are not irresistible. It is possible to defeat them. My guess is that they will lose some points in the Bundesliga before the Champions League match. Because Champions League matches are more important. So before the Champions League match they will send the star players to rest, forming a relatively weak team.
Yes that can happen but even their replacement players are capable to win games they have many stars in their squad even if they do lose points there is no other team consistent enough in their results to threaten them so even if they lose some points dortmund will lose points too.