To reproduce (on Mac), type "table" + tab. The table open & close tags gets created. Without moving the cursor, hit 2 returns then move up so the cursor is in the middle like so:
<table>
[cursor here]
</table>
If you now type "tr" + tab, the <tr> tag isn't created as expected. If however you delete the letters "tr" then try it again, the tab completion does work this time around. Seems like a bug.