It's not just the voiceovers that are wrong, in Alderaan Civil War sometimes me and my team get put into the actual Republic shuttle (I'm an Imperial). The game seems to recognise us as Reps for some reason.
I don't think that's a bug, because it happened before 1.4 anytime a match was Imp vs. Imp or Rep vs Rep. One team would randomly get the other faction's shuttle. What is a bug though is the voiceover. For the three warzones that aren't Huttball, any time there was a same faction match, there would be a commander voicing everything. Now you can be Imperials fighting other Imperials, and you will hear Satele Shan on Voidstar or a Republic commander in Novare Coast or Civil War.