Cubase 6 unusual audio echo recorded

Hello, running Cubase 6.0.7, on Windows 7 64bit. Using Focusrite Liquid saffire 56. Running into a weird problem with an echo on recorded audio, where I getting a single “slap back” echo. This is not a monitoring issue, only a playback problem. My room is acoustically treated, and the strange thing is that if I play the track using the speaker or scrub tool, there is no echo. It only happens with transport play. There are no inserts, sends, reverb on the track- just plain vocal, recorded with Avantone mic. Panned center, no track delay, but it sounds like a 30 millisecond slapback. Hear it through headphones and monitor. I’m stumped. Saffire MixControl set to monitor DAW 1 and DAW 2. It’s like the signal is being picked up and routed back. In the project, I’ve got all the other tracks muted. Does anyone have any ideas? This is stopping my project in it’s “tracks”.

So not just from mic- guitar connected directly also has this slap back echo.

Think that I discovered the problem. While there was no delay or reverb on any of the tracks, I forgot to check the master volume- there was a reverb insert there. Problem is resolved.