I suspect dialectal variation is involved concerning whether "has Vpp" is used properly with "since" in relation to durative and punctual predicates in the following. Note also that dialectal variation is not restricted to AmE/BrE difference; it could also involve internal differences within AmE or BrE.
It is over 20 years since John has died for his country.
It is over 20 years since John has lived in this country.
I've seen the following sentence in Practical English by Michael Swan:
I've known her since I’ve lived in this street.
If you reject the first two sentences, do you reject the third one? If not, could you explain the difference?
Previous threads do not deal with the variation in acceptability of present perfect in since-clauses.
I've known her since I’ve lived in this street.
– Apollyon Nov 01 '21 at 09:57I am wondering if "has Vpp" is used properly with "since" in the following:No wonder Astralbee is peeved and refuses to address the third and ONLY grammatical sentence. – Mari-Lou A Nov 01 '21 at 15:09