That is very possible to happen. Even though Leverkusen are still unbeaten, I doubt they will be able to consistently maintain their performance until the end of the season? Xabi is an extraordinary coach who is able to make Leverkusen a strong team but the problem is that Munich has everything to win the league.
Leverkusen are doing well but they must be realistic with their finish in the season. They can win Bundesliga but they must be realistic that they don't have to aim at unbeaten record in this season. Just win Bundesliga is already magic for them and for the league after many years under domination of Bayern Munich.
They also will have to play in Europe and it can drain their energy in upcoming months and matches. If they want too much, have too ambitious target, they will face with losing all when they are closely to the finish line.
Especially in the transfer market, if they can bring in some strong enough players then I think this competition will be determined in the last few games at the end of the season.
Is this for Bayern Munich? They actually have better finance than Leverkusen and can get new supplementary players in January to improve their squad and make difference against Leverkusen. Leverkusen with smaller financial budget, won't be able to use the same approach like the competitor.