File export - start of audio missing

I’ve got a problem with a current project in C10. I set the markers and export and about 1.5 seconds of audio is missing from the start. I’ve tried to export mp3, 16 bit wav and 24 bit wav and have the same problem. I thought a quick fix would be render in place but that also has the start of the audio missing (the file is the same length, there’s just 1.5 seconds of silence then audio starts abruptly). If I set the first marker to a couple of seconds before the audio starts then it exports ok, but then I have a gap at the start of my audio file which I don’t want. I know I could edit this using a different program but I do a lot of exporting in Cubase and don’t want to have to use 2 programs every time to edit the gaps out of the file. Does anyone know what could be causing this.