This has been a known issue since the beginning. Currently (as of Revit 2014), Revit is unable to adjust to rotation of embedded elements of vertically hosted families to accommodate to the View. There are two options to bypass this limitation:
1. Use Tags instead of an embedded Label. Tags will, of course, remain readable to the current View. The disadvantage of this method is that you will have to remember to Tag the element in every View in which is it need to be, creating the possibility that it can be missed.
2. Modify the embedded Generic Annotations so that they can be manually adjusted. Two possible techniques are:
a.) Place 4 instances of the Generic Annotation in the Family rotated at the cardinal directions and key each of their Visibilities to a corresponding Yes/No Instance Parameter.
b.) Create rotational constraints for the Generic Annotation, which can be tedious, tricky, and trying.
**Note that Revit is not very good at handling the rotation of Text and Labels cleanly. As a result, I have created special Generic Annotations that represent the alphabetical characters as line work, in lieu of using actual text.
Attached is an example of each technique (a & b) for #2 above.
This is definitely an issue that needs to be addressed, so I would advise using the following link (which it frequently provided by Autodesk personnel here) to report this issue with Autodesk Product Support.
Autodesk Product Support
"The following link is setup for you to submit feature requests, or feedback, directly to our Development group:"