This is not quite true.
First, though, There never has been an H1B "transfer". What was possible was to apply for a new H1 and begin working at new job BEFORE approval, as soon as the petition was recieved by USCIS. This is known as "porting" one's H1-B status to another (second) employer. This could be done regardless of what status you were currently in (ie. you could have lost your job months earlier, and either becoem a tourist, a student, a
Tn or an H4/TD spouse).
This still exists, but now one MUST be still working for the 1st H1B employer up until the new one is submitted in order to begin work immeditely. Otherwise, they cannot start to work until the new H1 is approved.
Second, this is not a new rule, it is simply a clarification by USCIS of what they consider a proper status for this porting to begin under.
Nothing of this would impact your Gf. She always needed to have the second company apply for an H1 for her (so this has not changed), and, because she presumably will be working at company #1, she can start at company #2 as soon as they file H1 petition (so she is not impacted by this clarification). She will be continuously in H1 status, and thus can start at Company # 2 immediately after petition is filed.
Btw, she would never have had to leave the country for a year in any event. Once one has had an approved H1, they can ALWAYS get subsequent H1's as long as they have not worked 6 years in H1. Nothing about that has changed.
Sounds like you are getting bad rumours.