Merged track issue

[Speed]

This could be user error, but I have some songs made in mp3 cutter and merger app to combine half of two songs into one. On regular version of app if worked fine, in the test version it has took the same file and made the two songs full length. Both songs still play but the cut marks are gone. I deleted the file and got a clean copy of it. When I opened it it said the right amount of time but once it started playing it changed back to full length again. I switched out of test version and it converted back and worked like before. Any help will be appreciated.