It is so funny to see how things doesn't last forever, look at Leverkusen who won the league unbeaten have gotten their first defeat since last season till the season by Leipzig. This shows that they might not be able to defend the title and a different club might win the league this season. If it happens so, it means that Bundesliga is becoming unpredictable.
Leverkusen has a lot of challenges this season because they will be playing in UCL which might be a distraction to them from staying focus on winning Bundesliga this season.
I'm sure you weren't expecting Bayer Leverkusen to finish this season's Bundesliga campaign without conceding a defeat just because they achieved that feat last season.