The reigning Bundesliga champions twice led through Arjen Robben and Joshua Kimmich but Szabolcs Huszti and Marco Fabian both got on the scoresheet to earn a share the spoils.
Bayern are on a sub-standard run at present, having had to also settle for just a point in their game before the international break against Cologne.
Rummenigge was extremely disappointed with Saturday's result at the Commerzbank-Arena and feels Bayern must do much better ahead of their Champions League clash with PSV Eindhoven on Wednesday.
"That was not worthy of FC Bayern," Rummenigge said. "We do not experience something like that so often.
"Today we must be satisfied with a point, like we started the game with."