Newer LEDs malfunction in the same way. I have had to re-install one incandescent in a circuit of two or more lamps. In this case all the LEDs stay on steady at a low level. When I put in an old bulb problem solved.
In another case the light switches had the neon find-the-switch-in-the-dark toggles. The CFLs went crazy, and one incandescent fixed it.
