Is your Snapchat export affected?
If your JSON has download links (working)
Your memories_history.json contains Download Link and Media Download Url fields — your export will work fine.
If your JSON is missing them (broken)
If those fields are missing or show NA, your export is affected by a recent Snapchat bug. There's nothing you can do right now — wait until Snapchat fixes the export and re-download your data.