Before batch preprocessing the filter name was 'Filter 1' (or for other filters 'Filter 2', etc).
The master flat was generated with a Filter keyword of 'F'
When I load those flats into the batch preprocessing script it fails to match up on the correct filter (puts the different filters into the same filter group 'F').
Sample generated flat file name, fwiw:
flat-FILTER_Filter_1-BINNING_1.fit
