The latest release of eccodes version 2.7.0 uses the Apache license, and includes this license in the root of the source in the file LICENSE (which is fine).

However, there are still some files in the software package that use a different license:
GPL (v3 or later)
-----------------
eccodes-2.7.0-Source/src/grib_yacc.c
eccodes-2.7.0-Source/src/grib_yacc.h

LGPL

eccodes-2.7.0-Source/src/grib_accessor_class_bufr_data_element.c
eccodes-2.7.0-Source/src/grib_accessor_class_pack_bufr_values.c
eccodes-2.7.0-Source/src/grib_accessor_class_unpack_bufr_values.c
See also comment 22 in https://bugzilla.redhat.com/show_bug.cgi?id=1508950

is this intentional, or is this by mistake?

If this is a mistake (and it seems to me this may be the case for the last 3 files), please correct it.

If this is intentional (as is the case for the first 2 files I think), then please mention this in a text file in the software root.

Note that there is a convenience perl script named license.pl in the software root that mentions two licenses, but this is not really something that I would expect to be used to present this information to the users.