Custom print filter in non-standard location is not found by CUPS

Issue

We use a third-party PPD file with a custom driver. The print filter script specified in PPD file is /pro/scripts/cups_ptfilter.sh. When adding a printer using the PPD file, it adds /usr/lib64/cups/filter/ prefix to the filter script to create /usr/lib64/cups/filter//opt/scripts/cups_ptfilter.sh. For Example:

# lpadmin -p r016 -v lpd://printserver/r016 -m DtaLaserPrinter.ppd -E
# lpstat -t
scheduler is running
no system default destination
device for r016: lpd://printserver/r016
r016 accepting requests since Fri 17 Mar 2023 03:24:42 PM SAST
printer r016 is idle.  enabled since Fri 17 Mar 2023 03:24:42 PM SAST
       File "/usr/lib64/cups/filter//opt/scripts/cups_ptfilter.sh" not available: No such file or directory