All emails are sent from the same address
Ah - yes that sounds like a regression. This is working fine in 4.6.28 - I just confirmed that in 4.6.28 the From is (correct) the Email that I am selecting from the From list - and not the default From as configured in:

civicrm/admin/options/from_email_address?reset=1


Open a JIRA ticket for it to try get some attention to this issue. Label it with regression - and any detail you may have e.g. do you remember when this was last working?