[tempay]

The bytes of the compressed file are non deterministic and depend on the number of cores used, system load and other “random” factors.

[shmerl]

Can't you set those parameters during compression to something fixed? Should be doable.

[esotericn]

Or you can just use zstd.

The xz tool is not deterministic when compressing. The packaging team might change upstream for a few things, but diving into the innards of a compression tool is expecting a bit much.