Added spring washer and replaced coil sleeve on left flipper. That took care of the sticking.

For right flipper coil added a spring washer and replaced coil sleeve. Coil now doesn’t wiggle when flipped.

Left flipper coil had a lot of wiggle to it, and the sticking seemed to be related. I tightened it vigorously, which helped, but it could perhaps use a spring washer to make it more stable. I’ve ordered some.