TYPO3 Core

i added a smiliar ticket not long ago.
the indexer chrashes because of files with special characters.
Probably the solution is to replace another substr with mb_substr, but i can't find the line.

Oops, an error occurred!
An exception occurred while executing 'INSERT INTO `index_phash` (`phash`, `phash_grouping`, `static_page_arguments`, `contentHash`, `data_filename`, `item_type`, `item_title`, `item_description`, `item_mtime`, `item_size`, `item_crdate`, `tstamp`, `crdate`, `gr_list`, `externalUrl`, `recordUid`, `freeIndexUid`, `freeIndexSetId`, `sys_language_uid`) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)' with params [196267543, 217192188, "{\"key\":\"1-1\"}", 227775705, "\/fileadmin\/prozessmodell\/F-PM-FB-08_-_Private_T%C3%A4tigkeit_im_Unternehmen_-_Laufzettel.pdf", "pdf", "\x4d\x69\x63\x72\x6f\x73\x6f\x66\x74\x20\x57\x6f\x72\x64\x20\x2d\x20\x46\x2d\x50\x4d\x2d\x46\x42\x2d\x30\x38\x20\x2d\x20\x50\x72\x69\x76\x61\x74\x65\x20\x54\xe4\x74\x69\x67\x6b\x65\x69\x74\x20\x69\x6d\x20\x55\x6e\x74\x65\x72\x6e\x65\x68\x6d\x65\x6e\x20\x2d\x20\x4c\x61\x75\x66\x7a\x65\x74\x74\x65\x6c\x2e\x64\x6f\x63\x78", "\uf0a3 \uf0a3 tum + Unterschrift", 1605686050, 214931, 1605686050, 1622457776, 1622457776, "0,-1", 0, 0, 0, 0, 0]: Incorrect string value: '\xE4tigke...' for column 'item_title' at row 1