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.
There was never a chance that Leverkusen was going to still maintain the same record of staying unbeaten this season long, but they can try to not loose so much but only a few losses that way they will not really be taken out of the title race by the end of the season aor ruined their chances of still maintaining the title. I'm seeing that if the pressure is maintained, or possible they may not get the trophy again this season but xavi has got a very sound team and all that he needs to win this trophy so I don't expect him to be challenged so much to the point he loses out in the title race by the end of the season because he definitely has what it takes to secure the trophy again in Germany.