Darkening audio after gluing

Why is it when an audio track/s have been split and you then decide to reglue, the track in question changes to a darker shade - sometimes leaving evidence of the earlier split in the form of a dark line?
Thanks in advance.

I’d like to know this too Gav.

Darker shade = You created an audio part

Are you sure you’re not making a “Part” when gluing events together?

It’s my observation that if you cut a part in two and change any characteristic of either side, it will darken the result when you glue it back. If both parts are left unchanged, it will glue back in it’s original state. It would be my guess that the darkening constitutes an altered state.