UEFITool is totally fine there, despite the changes in APL descriptor (which are very minor compared to Skylake one, Reserved1 region is renamed to Device Expansion region, and that’s about it).
The problem with that images is the vendor made a mistake in last volume size, so it’s free space crosses regions boundary, that’s what that error message is all about. If you correct FvLength of the last volume manually to not cross the 0x6FEFFF, the file will be parsed normally.
The problem is that vendor don’t see that volume free space is outside the BIOS region, but UEFITool sees that and complains about it. As a workaround, someone can add a routine to correct this last volume size automatically during parsing., or tell the vendor that they are doing their images a wrong way.