InnoDB can wrongly ignore the end of data files when using
innodb_page_size=32k or innodb_page_size=64k. These page sizes
use an allocation extent size of 2 or 4 megabytes, not 1 megabyte.

This issue does not affect MariaDB Server 10.2, which is using
the correct WL#5757 code from MySQL 5.7.

That said, it does not make sense to ignore the tail of data files.
The next time the data file needs to be extended, it would be extended
to a multiple of the extent size, once the size exceeds one extent.