"If it's not the same as the bulb
connected to hot and neutral, you have a faulty ground. "

Not necessarily. There is some voltage on neutrals in some places. This is caused by heavy loading on one side of the 240 compared to the other. It can be worse if common neutrals are used.

Saw one place that had like 20 volts on the neutral because of two 110 volt window AC units that happened to be on one side of the line.