What does “[Invalid UTF-8]” error message mean? What do I do?

When setting up China Chinese Ibus pinyin Writer input in Mint 17.1 Mate, I am offered a choice of five character sets. I chose UTF-8, which I believe is the usual Unicode character set. I find that regularly, instead of inserting the characters I choose, I get “[Invalid UTF-8]” printed at that point in the file.

What does this mean? It isn’t self-explanatory. Which character set should I be using to avoid the problem? I’ll be grateful for answers.

Not a LO issue. This issue has to do with language support in the host OS.

Ubuntu: “The ibus-pinyin package is broken and should be replaced by the ibus-libpinyin package”.
Fedora: Try disabling/unchecking ‘Use custom phrases’ in Preference->Dictionary.

Reference: Invalid UTF-8” in Chinese input

PS. The reference goes to a post at askubuntu which appears to have been submitted by yourself, haha. Looka like you found a better forum to ask the question in.