Hi, Alan,
I almost never get on Melodica World anymore and I guess I didn’t check the box to have this topic send me emails (I have now), so I just saw your post.
I don’t remember exactly what I did, but I believe I went back and re-gapped any reeds that looks widely different from their neighbors. I haven’t had a blocked note in months, so this must have worked.
I wound up using a magnifying glass to check the gapping, which made gapping differences really stand out.