Why does my PCR screening fail in BAC recombineering, even though antibiotics resistantce suggests successful BAC DNA transformation?

I'm working on BAC recombineering. I've done electroporation of BAC DNA into the SW105 cells and got antibiotics-resistant cells, indicating that my BAC DNA was successfully introduced into the cells.

However, PCR screening doesn't work well using the growth and extracted BACmid, but not single colony.

I usually got several extra bands as well as the desired bands in my PCR, but the signal of extra band is always stronger than desired ones.

Is it possible that bacteria can acquire antibiotics resistance with degraded plasmid?