If you are using Copy/Paste you copy all the events.
This includes Program Changes. Are you accidentally making copies using Copy/Paste?

If you check the Data Filter box during the Copy process you can limit what all you are copying .. and much more
Just in case it may be the cause (or may still help some users)

Attached Files (Click to download or enlarge) (Only available when you are logged in)
DataFilterPatch.jpg (72.36 KB, 68 downloads)

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