I would say some one has got the labels the wrong way around. Some switches can use the current through the bulbs to power them, but much depends on the design of the bulb, it can cause them to stay on dim, or flash, when off, and can also cause a shimmer when switched on.
I have with the Energenie switches found some bulbs will work A1 with no capacitor
others even with the capacitor they have a shimmer when switched on, and only way to find out is try it.
This is why I changed to type with battery to power them. Living room, dinning room, my bedroom, wife's bedroom and office all had Energenie light switches. And only my wife's room with 5 x G9 bulbs to start with caused a problem, swapping bulbs
the large one instead of small one cured the problem after many other attempts, however as time went one, one by one the switches turned into flasher units, and now only 2 of the original 5 still working.
Living room, dinning room, back kitchen, vestibule and outside lamp are now Tapo, craft room all smart bulbs, landing light smart relay, lower bedroom smart bulb, 2 outside lamps smart adaptors and three a smart bulbs one which will tomorrow be turned green. I have a whole mixture of ways to control lighting, with far too many apps to set them up, but they can all migrate to the google home app, so once set up all use same app, and work with google Nest Mini speakers.
Each method has a plus and minus against other methods, but in general smart bulbs are so much easier, in the main that is the way to go.