Hello,
It is not possible in any way that the VintageWarmer it self (and any other plug-in as well) could make such a job. The plug-in only process the signal in floating point format and have no access to audio files. I guess that the Wavelab can do something strange with those files or there is a configuration problem (or 16-24 bit mismatch) somewhere, for instance input files are 16 bit and output files are 24 bit which may confuse the ProTools.
I guess that there might me many other reasons of this problem but it is rather not related to any specific plug-in.
Regards,
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Mateusz Wozniak
PSPaudioware.com