You’re using the reserved public query variable name
as your custom one.
It can e.g. affect the canonical redirect by setting page_id
and name
for a different page.
Change it to something else to avoid possible name collision, like kenan_video_slug
:
add_rewrite_rule(
'^watch/([^/]*)$',
'index.php?pagename=watch&kenan_video_slug=$matches[1]',
'top'
);
Note that your rewrite will override the content pagination for the watch
page.
Remember to flush the rewrite rules.