There have been quite a few reports about this YouTube issue recently. Looks like a YouTube bug where JavaScript always interprets a space bar and other characters as control keys and do not disable this action when an input field has focus. See also: *[/questions/1328819] Youtube search bar issues ---- A possible workaround for now is to write text or affected characters elsewhere (e.g. in the location bar) and paste the clipboard content in the search bar or comment field. ---- There are some bug reports about this issue filed, all duped to this bug where you can keep an eye on. *[https://bugzilla.mozilla.org/show_bug.cgi?id=1697551 Bug 1697551] - Unable to type spaces and other characters (f, m) into YouTube search bar (<i>please do not comment in bug reports<br>https://bugzilla.mozilla.org/page.cgi?id=etiquette.html</i>)

Hi Thank you for flagging up this issue. YouTube have looked into this and will be correcting the issue shortly.