Im doing the very same but didnt have time to look into the multi instance loop. Your process variable for the computer systems isnt of type "object" so i dont think you can loop it right away. Im using string functions and gateways to manually loop through the selection. I was thinking of using a "get entries" where i build the query based on the multi select answers and use that result (of type object) to loop. Doing so i still needed to use string functions to create the query so i went for the workaround of my own loop.
I believe the answer for your question is that you need a variable of type object to be able to loop. That is a local variable so it isnt possible to map on your questionaire. What you get from your multiselect dropdown is just a json formatted string. You can use that to fetch an array of objects but you cant use it directly in your loop.
thx for your answer!
At the moment we have DWPC 18.02 installed, the string functions are not available in this version, and I can't create my own loop like you do.
I also tried to map it to an object, but as you already said, this is not possible...
I would like to know, what the developers idea was how we should use Multi-Select dropdowns in 18.02. I don't see a way to use this right now. (Of course I create a REST-API which will then return a Object that I could use for a multi-instance loop but I can't belief this is the way it should work ;-) )
We are currently planning to upgrade to latest Version, but it will take sometime until we have this up and running in Prod environment...