How do I fix timing issues on a cakewalk project?

[Azrend]

I was opening a project that I had copied (using "save copy as").

I played it back, but I noticed that some notes were not synchronized to when I had placed them. The lead instrument, for example, would start playing early, even though the placement of the note is where I want it to be. However, everything sounds fine when I export it.

It sounded fine when I saved it, so why did it get messed up when I opened it?

Edited June 15, 2020 by Azrend

[Promidi]

Which version (Numerically) of Cakewalk are you using?

In 20 years, I have never had this issue - and I use "save copy as" all the time.

Can you give a bit more information?  Are you using VSTi plugins or hardware synths.  If using VSTi plugins, are you using any effects on the tracks