Will be reporting via normal channels, but putting this out so that anyone else who runs into it can avoid having to dig through and figure out why it happens – especially since it is not particularly obvious what is wrong, based on where it fails.
On line 32 of HoudiniEngine/Source/HoudiniEngine/HoudiniEngine.Build.cs change
string HFSPath = “Ccygwin64/home/prisms/builder-new/Nightly14.0/dev/hfs”;
to
String HFSPath = “”;
(this causes the auto-detection to kick in properly, or at least appears to)