It would be unfortunate if mistakes were perpetuated simply because our revered teachers were not aware of the correct pronunciation. I know of no gemara that mandates errors or mistakes. בלשון רבו does not mean בטעויות רבו.
I also heard as a young man only B’chaye, but it turns out that it is incorrect. No one’s fault, really, over time many words become adulterated, it’s part of language and dialect development. Rabeinu Bachye lived in Moslem Spain in the 11th century and not in Bobroisk or Eishishok in the 19th century. However, the correct pronunciation is Rabeinu Bachye or possibly Bachyai. Please tell your rebbeim, I’m sure they also would want to pronounce someone else’s name the proper way.