Can't generate tags using universal-ctags

I have a bunch of markdown files in which I have tags defined using "#",
something like #tagone #tagsomething.

In $HOME/.ctags.d/md.ctags I have this

--langdef=markdowntags
--languages=markdowntags
--langmap=markdowntags:.md
--kinddef-markdowntags=t,tag,tags
--mline-regex-markdowntags=/(^|[[:space:]])#(\w\S*)/\2/t/{mgroup=2}

But when I do "uctags -R ." I get no tags in the tags file.

With the same files, the same configuration in FreeBSD and Alpine Linux I
get the expected result.

Thank you!