I have seen this once on a gravestone in Vienna of my g-g-g-g-g aunt Rosa FISCHHOF geb. FRIEDLAENDER (ca.1787-1860). Her father was named Joseph FRIEDLAENDER and her oldest son was named Josef. It seems unlikely that the father's name could have been forgotten, since the namesake grandson was around for over 50 years (though he did die 3 years before his mother). Based on the birth of the namesake in 1804, and the the seeming re-marriage of this wife in about 1804 (had a son in 1805),I have assumed that Rosa's father died in 1803 or 1804.
There is no reason to doubt that Joseph FRIEDLAENDER was Jewish. However, I could entertain the possibility that he did not die in 1804, but instead that he converted to Christianity around that time (no evidence), leading to a divorce from his wife (no evidence) so that she could re-marry ca.1804 -- and leading to his omission from his daughter's gravestone. (Though his daughter did name a son after him in 1804; not so likely if had converted and not died.)
I have wondered about this reference to the mother and not the father on a gravestone, but have not learned the reason for this specific instance or the occasional appearance of this phenomenon.
All the best,
Point Roberts, WA, USA