Can I switch jobs after GC stamping but before getting card?

[imminovice]

My GC was approved and I have got my passport stamped very recently. I am now waiting for my plastic card.

In the meantine I was planning to quit my sponsoring company to join another company.

I have heard that you need to wait for atleast 6 months after GC. Is that essential?

Is the 6 months from approval notice date, passport stamping date or the actual card issue date?

Appreciate your help!!!!