Full text indexing problem: Attachment cannot be indexed: Incorrect string value

I’m running into an issue with setting up full text indexing, which I believe is related to character set in MariaDB. Is there a way to skip or deal with these?

/opt/rt4/sbin/rt-fulltext-indexer

[6932] [Tue Jul 23 16:00:26 2019] [warning]: DBD::mysql::st execute failed: Incorrect string value: ‘\xB3\xF6\xCA\xDB\xC8\xAB…’ for column rt.AttachmentsIndex.Content at row 1 at /opt/rt4/sbin/rt-fulltext-indexer line 238. (/opt/rt4/sbin/rt-fulltext-indexer:238)
[6932] [Tue Jul 23 16:00:26 2019] [warning]: DBD::mysql::st execute failed: Incorrect string value: ‘\xB3\xF6\xCA\xDB\xC8\xAB…’ for column rt.AttachmentsIndex.Content at row 1 at /opt/rt4/sbin/rt-

Is there something I can do to skip tickets like this?