Bought a simple table lamp. It has a brass bayonet lamp holder with integral switch.
Put bulb in. Plug in. Switch on. Works.
Switch off. Change bulb. As replacement bulb is pushed into the lamp holder, it flashes on.
This is repeatable - if the prongs that contact the base of the bulb are pushed down, the lamp lights. When you have given the bulb the turn needed to engage the pins and leave go, it switches off.
Exactly the same happens whether the bulb is a standard filament or a CFL.
This seems very wrong to me. Anyone care to comment?