Acid files bang in extra metadata as split mentioned,
when rendering in Acid, if the Timestretch settings in acid are incorrect (many users overlook this) it will print the File with default metadata, usually 120bpm, Key A…
PITA…but it is why youll get it with some files and not others.
I would also remove the data it stores in the file from mediabay, as it can use the data it collects to stretch your file.
Use the mediabay to tag correctly before importing your file into your project for more control of what Cubase will do to it when it lands on a track. 