As of a few snapshots ago, exiting the resource pack menu no longer refreshes the list, meaning that you have to restart the game entirely or put on and remove an already visible resource pack for it to register a pack that wasn't in the folder prior to the game opening.
MC-190863
Resource pack list no longer refreshes after exiting the menu and going back in
Resolved
Duplicate
0
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However, we are already tracking this issue, and this report is a Duplicate of MC-188473, which is a report that has not been resolved yet.
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