When writing the un-binned data to a fits file, the meta data includes the keyword "data_file". There are two problems with this.
If the name of the file is too long, this will cause an error (as found by @eneights). This can happen because the code is using the data file name in the inputs yaml file, which often contains a long path.
This meta data doesn't apply when combining multiple fits files.
When writing the un-binned data to a fits file, the meta data includes the keyword "data_file". There are two problems with this.