MariaDB LOAD DATA INFO can't import single column file to single column table?
To quote the manual:


  If you specify no FIELDS or LINES clause, the defaults are the same as if you had written this:


FIELDS TERMINATED BY '\t' ENCLOSED BY '' ESCAPED BY '\\'
LINES TERMINATED BY '\n' STARTING BY ''


and


  Interpret characters preceded by the escape character \ as escape sequences. For example, \t, \n, and \ signify tab, newline, and backslash, respectively. See the discussion of FIELDS ESCAPED BY later for the full list of escape sequences.


and


  If the FIELDS ESCAPED BY character is empty, escape-sequence interpretation does not occur.


and


  ... empty ('')


-- https://dev.mysql.com/doc/refman/8.0/en/load-data.html

That is, if you have tabs or backslashes, the data will be mangled as it is read.  This may explain the problem you are having.

I guess this may be the fix:

FIELDS ESCAPED BY ''