I found beholder is pronounced like [bihóuldər] but I heard some speaker in the VOA pronounced it like [bəhóuldər]. Which one is right? Are native speakers confused with them?
Which one is right?
[bihóuldər] is technically the correct pronunciation.
Are native speakers confused with them?
As a native speaker, I would say no. Furthermore, I would also point out that it seems very common to use a "lazy" pronunciation and to say [bəhóuldər] (at least in the United States).
To my (American) ear, both pronunciations are correct. I use both pronunciations myself. I prefer the unstressed first syllable (with the schwa).