I faced a problem when the autocomplte feature stopped working correctly in one of my .html documents.
Specifically, when I typed ".foo" + "Tab"
l expected it to generate <div class="foo"</div>
while it generated .<div class="fo"></div>
so it left the dot and removed the last letter from the class name. After some searching, it turned out that I had an emoji up the document () removing which solved the issue.