I upgrade my TeXmacs (on two Windows machines) to version 1.99.12.
I think the completion by a tab key in the cite and cite-detail stopped working. Actually, it may stopped working already on some previous versions, but I am not completely sure of this.
I also tested under Arch-linux (simulated using WSL). It also does not work properly.
I am checking the code to see where it is wrong.
I have tested the following code according to the call of the completion:
(define u (current-bib-file #t)) ; <url /mnt/c/***/***/data>, without bib suffix
(url-last-modified u) ; this returns a negative number -2147483647
(url-last-modified (url-glue u ".bib")) ; return correctly
When I changed (url-last-modified u) to (url-last-modified (url-glue u ".bib")), the cite completion still fails.