Shower pan failure-Plumber used yellow pipe dope under membrane.

We tore the shower apart and found that the "sealant" used by the installer was yellow plumbers putty. By this time it was totally diluted and runny, and sealing nothing. The capillary action between the drain and the membrane totally soaked the mortar bed, the treated wood curb, caused the curb to swell and allowed water to flow under the floor tile outside the shower and through the grooves in the thinset under the tile and kept the space under the tile in the entire bathroom wet. Being replenished with new moisture daily. Result: mold, throughout the home.

Youtube tells me silicone sealant should have been used to seal the drain flange to the membrane. Is any other kind of cement or sealant appropriate?

Can you post pictures? Plumbers putty is just that, it's putty. It's state does not change from putty to something runny. Worst case scenario after 10 years it goes hard and crumbly.

he has got to be referring to rectorseal #5