I'm in a rented house and there is one light switch that has tendency to "bounce" when turning the lights off. It sometimes "bounces" back.

It feels like there is some kind of magnetic resistance.

What could cause this?

Ants nest maybe. Or weak spring.

spring, install a new one!

Spirits, get a monk in the chase it away

Bad switch...a broke component inside...probably part of the plastic assembly inside.. I've had several wall switches break over the years in my 8 year old Thai home....being me I would always disassemble the defective switch to see what failed and so far it's always been some small plastic piece broke inside which holds the internal switching assembly in the correct position. I've yet to have one fail due to defective/burnt metal contacts within the switch...it's always been some piece of internal plastic that broke. Summary: replace the switch.