Here are all important links:
http://lmms.io/forum/viewtopic.php?f=1&t=4740
-A few rules and useful forum instructions
That is hard to digest. I propl. need to see the project..
But one thing that can cause that is if you have enabled loop, and accidentality have chosen the setting export-between-loopmarkers If not and you are on 1.2.0, zip the project, upload it and send the link to me in a PM