Cannot remove compressed rests

I've run across an issue whereby the whole score thinks it has to use compressed rests and I can no longer add single measures - or break the compressed rests into separate rests. I arrived here by deleting all the notes from an existing score that happened to contain some compressed rests. My intention was to create a template for a new score. Any way to salvage this? The offending file is attached in case anyone can help me sort this out. Or maybe it's a bug? Any help appreciated! Thanks.