Two power and two neutral wires in 3-way light junction box

Hi,

I'm replacing a ceiling light that is powered by two 3-way switches. When I removed the ceiling light I expected to find one power and one neutral wire connected to the light fixture. What I found was two power wires connected together with a wire nut which then was connected to the light fixture via a pigtail. The same wiring arrangement was for the neutral wires. The house wiring is via EMT so the ground wire was connected to the junction box.

It looks like the 3-way switch is controlling another load on the circuit besides the ceiling light but I am not able to locate it. I went through each room and verified that lights turned on and outlets had power when the power to the ceiling light was off.

Is this type of wiring common? The house is over 60 years old so it may have been used as a short cut back in the day. I'm just trying to figure out if this is an issue or not. I've lived in the house for nearly 20 years without a problem and just decided to replace the ceiling light.

I'm thinking that I can just wire in the new ceiling light without any concern but figured I would ask the experts first.

Thanks in advance!