Multi-Wire Branch Circuit on wrong breakers

You may think there is nothing on that circuit but it needs to be verified. It is a simple fix to turn both breakers and swap the wires. Why is this important? With both hots on the same leg this overloads the neutral and this can cause a fire. Many years ago MWBC’s did not require handle ties or double pole breakers. People moving breakers around would split the pair and caused problems on the neutral. I have found panels where the neutral had gotten hot enough to melt its insulation and I was called when it melted into another live connector causing that breaker to trip. Since you understand the cable has 2 hot conductors that are sharing a neutral turn both breakers off and correct the problem by swapping the wires. Both are 15 amp so the wire size should be correct.

It doesn't appear that the red is on the same leg as the black, so the neutral should not be in danger of overload.

Prior to 1998 the NEC only required simultaneous disconnect for MWBC's if the two circuits were on the same yoke (like a split receptacle) or if it also fed line to line loads. So if the second circuit isn't in use it might not be a violation or dangerous if not altering electrical circuits. Because of the dangers that caused the Code to make these changes it is certainly worthwhile to have an electrician update your configuration.

You mentioned the 2P breaker fed a sump, I have done this intentionally with freezer and sumps circuits that weren't multiwire branch circuits to serve as a passive alarm, but a dishwasher seems poorly suited for that purpose. It looks like the bottom breaker is only half used, you could possibly replace it with a full size breaker and use a handle tie or two pole breaker and re-align circuits to maintain that passive alarm.