I have had issues with some unpacking utilities. Some work great with most archinves but chole on some newer ones. I usually go back to just using good old "LHA" from the shell and have almost no issues.
There's a bug in XAD LhA when using newer header versions. The newer versions of the LhA command line tool default to using a newer header version, so that's why you will see more problems with more recent archives.
The fix is to build xadmaster v13 for 68k.