Yeah, 바라(요) is the correct conjugated form but when it comes to 아/어 ending practically everyone says 바래.
What is the reason? I think it is because we subconsciously try to avoid giving wrong connotation. -라 is a sentence ending form for giving a command (크다->커라, 가다->가라, 하다->해라). So by analogy anything ending with -라 might automatically invoke this feel of giving a command in one's mind. When people say 바라, commanding or instructing is far from what they intend to say (it is just present indicative conjugation), so they instinctively change the pronunciation to avoid this unintended nuance which might come into play (for imperative of 바라다, we say 바라라, 바래라). So I think it is just a case of trying to avoid possible confusion.
There are just a few words that have 라 as the last syllable in the stem, like 나무라다 (scold, chide), and they seem to have a similar phenomenon.
Anyway, the thing to remember is to always use the correct form in writing. In speech, just go for whichever is more comfortable for you. People will understand whether you say 바라요 or 바래요.