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.