Zhuyin: Are both ㄧㄨㄥ and ㄩㄥ correct renderings of "yong"?

Question

I use https://www.yellowbridge.com/chinese/dictionary.php as my primary dictionary. For 用, and any character whose 拼音 would be "yong," the given 注音 on this site is always ㄧㄨㄥ. However, when inputting characters on a 注音 keyboard, it does not accept ㄧㄨㄥ, but rather ㄩㄥ. Additionally, a Taiwanese friend has told me that there is no such thing as ㄧㄨㄥ.

So is ㄧㄨㄥ just a weird alternate (but still correct) rendering of the sound in 注音? Or is this dictionary site in error, and it actually should always be ㄩㄥ?

Answer 1

Duke University hosts a: Character Conversion Table that may be of good reference for you.

• ㄧㄨㄥ = yi + weng
• ㄩㄥ = yong

I'd highly recommend not using yellowbridge.

Answer 2

ㄩㄥ is definitely the only correct rendering for 漢語拼音 HanYuPinYin yong.

Examples:

兄弟 ㄒㄩㄥ ㄉㄧˋ xiong di4

有用　ㄧㄡˇㄩㄥˋ you3 yong4

If you're interested, Cantonese zhuyin also doesn't use ㄧㄨㄥ https://zh.wikipedia.org/wiki/%E7%B2%B5%E8%AA%9E%E6%B3%A8%E9%9F%B3%E7%AC%A6%E8%99%9F