Yes. It is your traction control using the ABS system to keep a tire(s) from spinning. If it is doing it with the TC off, it isn't off. Bad Switch?
Traction control is always on - VDC elements get reduced or turned off. Meaning cutting your throttle to prevent excessive wheel spin is reduced when you turn the system off with the switch.
Traction control is wanted at all times given this involves using the brake system to slow spinning tires say for example the right side of the car is in a low spot and sitting on ice left side tires are on solid ground- the TC will brake the right side tires and the mechanical results is more power pushed to the left side tires. The ABS system is used by TC to do this.
VDC or vehicle dynamic control involves more throttle control ie reduction and is intended to do things that help a vehicle at speed - stay right side up, stay pointed in the desired direction etc. The advanced capability of newer VDC systems even help with over steer by putting brake pressure on the inside front tire to help correct over steer when someone plows into a corner going too fast.
VDC turned off allows the car to spin tires more and allows for more power to be sent to spinning tires for things like getting out of a snowed in parking lot, scrambling up a slick driveway or driving in sand or mud all cases where the TC system is still very much needed to help push power to tires that have grip and limit wheel spin on the tires that lack grip.
You guys are mixing two systems and their intended designed function together.
ABS will always work with VDC on or off. TC will always work with VDC on or off.
Some aspects of VDC will still exist even when turned off - for instance the car will not let you just spin tires to the red line with VDC turned off a few auto makers learned that there are plenty of stupid people who will do that to the point that a tire explodes and even catches fire!!!! Mercedes had a woman do that in an R series and turn it into a pretty major well known lawsuit.