10
It seems like there are some issues with your "utf8mb4_general_ci".
See these articles:
http://stackoverflow.com/questions/20411440/incorrect-string-value-xf0-x9f-x8e-xb6-xf0-x9f-mysql
https://mathiasbynens.be/notes/mysql-utf8mb4#character-sets
In the below article, he shows a picture where there are differences between individual columns
Maybe something similar is in your case, since XOOPS normally installs with "utf8_general_ci"
http://stackoverflow.com/questions/28540772/using-utf8mb4-in-mysql?rq=1
Why are you using "utf8mb4_general_ci" at all? I always use just the " utf8_general_ci"
Yeah - it's always the same - wrong configuration, operator error, and then blame it on XOOPS!
LOL