STR:

1. Write/edit an article.
2. Include in the article body an emoji pasted in. e.g. copy n paste this one: 🤬
3. Click Save.

ER: Article saved.
AR: Nothing. No confirmation announce message.

Other fields may similarly be affected.

Network console reports:

Fatal error: Uncaught mysqli_sql_exception: Incorrect string value: '\xF0\x9F\xA4\xAC\x0D\x0A...' for column textpattern.Body at row 1 in /path/to/textpattern/lib/txplib_db.php:442
Stack trace:
#0 /path/to/textpattern/lib/txplib_db.php(442): mysqli_query()
#1 /path/to/textpattern/lib/txplib_db.php(503): safe_query()
#2 /path/to/textpattern/include/txp_article.php(342): safe_update()
#3 /path/to/textpattern/include/txp_article.php(121): article_save()
#4 /path/to/textpattern/index.php(218): include('/path/to/...')
#5 {main} thrown in /path/to/textpattern/lib/txplib_db.php on line 442

Is this a) repeatable for other people, and b) expected behaviour or a bug?