Ok, finally figured it out by reviewing the javascript source code for expression manager.
This code is incorrect and results in the EM throwing a unknown variable error:
This is the correct code:
This code is incorrect and results in the EM throwing a unknown variable error:
{if(multiOpt1_1, address1_city, "")}{if(multiOpt1_1, address1_state, "")}{if(multiOpt1_1, address1_zip, "")}This is the correct code:
{if(multiOpt1==1, address1_city, "")}{if(multiOpt1==1, address1_state, "")}{if(multiOpt1==1, address1_zip, "")}