Data Map doesn't support sub var value as a member list

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Hi,

For specific design purpose, we have a sub var with the value as a list of members, eg. CC1,CC22,CC5,CC77. We then use the sub var in DataMap definition which validates successfully. But when we run the datamap, it throws error saying the sub var is undefined. If we change the value to be just CC1 then can be executed successfully.

It's weird that the definition accept the value as list, but don't recognize it when execute. The workaround can be using Groovy to parse the sub var and transit the list to override the datamap range instead. But want to understand why it's not supported, is this a BUG or maybe worth an ER?