We provided the documentation on how to mask a Parquet file.
The masking went ok with no errors except that the masked file is never written out. There are no errors in the log file.
FDM 4.11.170.0
Patch FastDataMasker-4.11.186.0.zip amd later resolves this issue.
TDM Patches can be downloaded from: Test Data Manager (TDM) Support Patches
How to apply patches can be referenced from this KB: How to apply patches for TDM