In the documentation for FLAC_ _stream_encoder_set_compression_level, there is a typo/formatting glitch such that every column to the right of max_lpc_order is pushed one column to the right. There are some extra tags in there).
See here, for example: https://xiph.org/flac/api/group__flac__stream__encoder.html#gae49cf32f5256cb47eecd33779493ac85
Very low priority, obviously.
Fixed. Thanks!