Quote Originally Posted by Cumulus View Post
6:22 - Двадцать две минуты седьмого она вернётся ...

Where did the preposition go?
(In other sentences, they DO use "в" for instances until the 31st minute: В четверть десятого ...)
Error in my book?
When answering "когда?" there has to be a preposition, of course:

7:20 Она вернётся в семь двадцать (в двадцать минут восьмого).
7:40 Она вернётся в семь сорок (без двадцати восемь).

As to your example ( Двадцать две минуты седьмого она вернётся ) I think it is incorrect. There are two possibilites:
1) There was a preposition in the sound recording, but you failed to hear it due to some reason.
2) In colloquial speech some people can say like that, but in fact there is an ellipsis (the full sentence should be in this case: [когда будет] двадцать две минуты седьмого, она вернётся).