Latency issue with new audio track on playback

Equipment is in signature.

I’ve recently come across a problem. When I record audio into a project I can play along with project and add audio in real time. e.g clean guitar into cubase and guitar rig used in insert…No problems.

Yesterday I added more instruments and on playback noticed that all the latest recording was out of sync. It was slightly delayed.

Have been through device manager and tried direct monitor on / off, have adjusted buffers etc but still problem occurs.

Drivers are fine as using latest MR816CSX as interface.

I even tried tapping guitar to a midi click from inside cubase to see if that was in sync… no it was not. Again guitar was delayed?

I tried a new project and problem disappeared.

Any advice? Please