The issued request looks like this: https://matomo.dev/piwik.php?link=https://example.com/&c_i=click&c_n=[content-name]&c_p=[content-piece]&c_t=[content-target]&idsite=1&[...]
If href is an internal link, content tracking works as expected.
Haven't tried it yet but this may be fixed by https://github.com/matomo-org/matomo/pull/15406/files in Matomo 4
Looks good, thanks for answering, Thomas! I'll close and test asap, and reopen, if necessary.