Because you're using an Infopath Form, I assume that it is the nature of that beast which is returning values to you in some type of XML format rather than a semicolon delimited string (which is how Nintex Forms returns multi-select values). 

I would recommend running your same test, but instead of only selecting one value, select both. 

Determine: 

• Did I get text with two (2) opening <Value> and closing </Value> tags like: 
  

  <Value>POC</Value>
  <Value>QC Inspector</Value>‍‍‍‍‍‍

  • If this is the case, then you should be able to wrap that XML-Like text inside of a parent node, and push all of the values into a collection using the Query XML Action.
    
    
    (this would hold the values from your forms, but I am not using infopath so I'm just going to hardcode them in there)
    
    By Wrapping that variable inside of some generic parent xml-like node,  you can easily xpath your way to success: 
    
    
    Now all of your values should live inside of that collection (in this example, named: 'var_someCollectionVar'). 
    
    
     
• Did I get text with one (1) opening <Value> and closing </Value> tag like: 
  
  

  <Value>POC QC Inspector</Value>‍‍‍‍‍

  • If only (1) Opening <Value> and closing </Value> tag were present, are the values inside delimited in some consistent fashion?
    
    

    <Value>POC,QC Inspector</Value>‍‍‍‍

    or
    

    <Value>POC; QC Inspector</Value>‍‍‍‍

    • Then we use the Query XML Action just like above, only instead of saving it to a Collection, we'll save it BACK to the var_InfoPathFormVals variable. 
      
      
      
      Doing this should leave us with a string like "POC; QC Inspector" or "POC, QC Inspector". Depending on the delimiter, you'll then set up a Regular Expression Action using the Split Command. 
      
      (That Pattern is ; being that it's a bit difficult to see)

Either way, you should now be able to parse the information in your workflow however you'd like. 

I hope that this helps. 

Thanks so much for your thoughtful and interesting solution. Selecting both values does indeed return "<Value>POC</Value><Value>QC Inspector</Value>" so I'm sure your approach would work, and when I get time I'll implement it because I like the precision of knowing those values exactly.

For the time being I went with a much lazier solution, simply testing the variable to see if it contains "POC" or "QC Inspector" (which works because this is currently the only use for the variable):

I guess my bigger concern is why did this suddenly change to be like this, and if it's some kind of global change (e.g. a SharePoint update happened) do I have this problem in other workflows but don't know it yet?

I ended up with the InfoPath form only because I selected that option for "Form type" when creating the workflow. Somehow it was created by Nintex (I presume) when the workflow was published. I haven't tried to touch or modify it at all....it's all out-of-the-box.

Thanks again for the solution!