It seems that in case doUseRegister=True, at

imageDifference.py: 828

# Third step: we need to fit the relative astrometry.

 #

 wcsResults = self.fitAstrometry(templateSources, templateExposure, selectSources)

 warpedExp = self.register.warpExposure(templateExposure, wcsResults.wcs,

 exposure.getWcs(), exposure.getBBox())

 templateExposure = warpedExp

the template got warped, but not its PSF and later the warping is not repeated. This is a bug. Consider whether this option is used in practice or just a leftover of an astrometry experiment. Fix or disable this option.

Note that the warping operation in ImagePsfMatchTask.matchExposures() looks ok but this is not used if doUseRegister=True. (L: 904 doWarping=not self.config.doUseRegister)