The chart halfway down this blog post lays out some of the challenges once the hanyu pinyin standard was instituted in 2009:
https://frozengarlic.wordpress.com/on-romanization/
The author concludes with this observation:
So that’s why people in Taiwan can’t spell anything consistently and why all the English-language newspapers spell the same things differently. As for me, I’m giving up on trying to remember how everyone spells their name. I know lots of people, especially Taiwan nationalists, dislike having the PRC hanyu pinyin system. I dislike imposing it upon them. However, in only three weeks, I’ve found myself spelling the same thing in multiple ways and wasting time looking up how I did it last time. Since almost no one reads my blog anyway, I’ll do it the way that’s most convenient for me.
I’ll also always provide the Chinese characters so that people who can read them know who I’m talking about.