I'm fairly sure this is not a bug and that in this instance, the person copied and pasted that text in.
Here's how it's actually laid out:
<input id="title" name="title" type="text" maxlength="300" tabindex="100" class="ask-title-field" data-min-length="15" data-max-length="150">
O.k. I found out what has caused this mess:
A script to add <kbd> shortcut functionality to the site
A greasemonkey script which is terrible outdated it seems but still is to be found on https://stackapps.com/questions/3341/kbd-markup-shortcuts
I found the cause of this, it is probably related to Firefox and some old, old cookies. I have sinced switch to 2-FA on google, and this probably had something to do with it. I cleared all cookies and re-logged in and all is well.
Thanks for bringing this up. I cannot reproduce the issue in the current build of our network sites. The layout for mobile has also changed considerably in the last 2 years. If you experience further issues please do not hesitate to report bugs.