Losing against a weak team doesn’t mean your performance is very poor but just due to their unluckiness in the game; if not, who would expect Dortmund to lose against such a team? So it is just not a good day for Dortmund; that is why they were not able to win because you also mentioned that in their game possession, Dortmund has 70% while Bochum has 30%. Moreover, even the 2 goals were so quick because it was just a 2-minute interval, so it was somehow difficult for Dortmund to maintain, but it came to see that Dortmund's performance has a default in their defence.
Nothing will make me think Borussia Dortmund loss because of how unlucky they are, that would be seeing a pen and choose to call it stick, Borussia Dortmund has abolish their performance, they lost because they cannot win, however was this match the first time Borussia Dortmund has 70%?, I no there are other long forgotten they also have 70% and loss, Bochum 2:0 impressive, relegation play off awaits them. Bayern Leverkusen and Bayern Munich decided for cutting into two weekend by 0:0 baring.