did you maybe multi-look your data?
If you want to go sure everything is fine, I can recommend the scripts provided by @mdelgado here: Snap2stamps package: a free tool to automate the SNAP-StaMPS Workflow
You simply place all slave zip files into a slave folder, create a master folder where you apply orbit files and TOPS Split and then the scripts do the rest for you including the export. I was able to get nice results with it.