Project not playing tracks in synch since opening it today

I’ve been working on a project for a few days in Cubase Pro 11 that has 3 different Halion tracks along with 2 real guitars and an electric bass (6 active tracks total). It’s been absolutely fine until opening it today. Now the “Audio” tracks (guitars and bass) are out of synch with each other, and with the Softsynths (key pads and percussion).
Furthermore, this came up today when attempting to do a 16 measure loop for recording a new bass part. As I set the loop for measures 39 to 55, rather than showing 16 measures, the locater range duration is showing I tried this at other points in this project, and the same types of things happened-e.g.a loop from measures 3-7 shows for locater range duration, rather than the 4 measures, as it should.
I opened other projects today and set loops in them to see if this was a problem throughout my Cubase projects, but it’s not. It’s confined only to this project I’m currently working on. Nothing was knowingly changed or reset between working on the project yesterday, when it was fine, and today, when it is now messed up. I’ve used Cubase for 9 years, and nothing like this has happened before.
Any help/suggestions would be appreciated. Thanks in advance.

I would check that your Primary Time Format is set to Bars + Beats and that Snap Type is set to Grid.

Many thanks for the suggestion. I checked that out and all of that seemed okay, but problem persisted. You did, though lead me to look in the right direction. My project had originally been 109bpm, and somehow that had gotten changed to 110bpm. Playback at 109 made everything sync correctly again.
For some reason locater change duration is still showing the wrong time display (as indicated above), although loops are going for the correct duration (16 measures). Not sure, why, but as long as I can work with the project, I’m good.
Thanks again.