If the song Musocity posted is your song, Gordon, I do see what you see, and I can't explain it.

You said there is a red line on bar 1. True.
You said F5 doesn't show any alteration. True.
You said you slowed it down on bar 1, but how did you do that?
The main tempo in the window above is 180 as soon as the song starts playing, correct? But then when you stop the song, it's 160. That's strange. And the song duration of 3:27 immediately changes to 3:03 to reflect the faster tempo. I think I wouldn't describe this as 'speeding up' so much as an immediate change of tempo from 160 to 180.

Nothing in the song memo gives a clue.

I don't think the style is overriding anything, because the default tempo of that old style is 140.

If no one else spots a cause of the mistake here, I recommend you freeze the song and email it to support@pgmusic.com and reference this thread.

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