Looping the messages struct results in exception, serializing and deserializing workaround allows looping the struct. see code and exception.

New Struct<br/>
<cfset MessageNew =DeserializeJSON(SerializeJSON(message.cids))>
<cfoutput>#SerializeJSON(MessageNew)#<br/></cfoutput>
<cfloop collection="#MessageNew#" Item="CurrItem">
<cfoutput>#CurrItem##MessageNew[CurrItem]#<br/></cfoutput>
</cfloop>

CFPOP Message struct<br/>
<cfoutput>#SerializeJSON(message.cids)#<br/></cfoutput>
<cfloop collection="#Message.cids#" Item="CurrItem">
<cfoutput>#CurrItem##Message.cids[CurrItem]#</cfoutput> /* results in key not found */
</cfloop>