VixDiskLib_Open fails in VDDK 7.0 using a vmPath in the vmxSpec

With VDDK 6.7.3 I could successfully call VixDiskLib_Open using a vmPath in the vmxSpec. In 7.0 I get the following errors:

VixDiskLib: VixDiskLib_OpenEx: Open a disk.

VixDiskLib: VixDiskLib_OpenEx: Failed to start session. Invalid search specifier: vmPath:/Shavlik/vm/ESXI6.7-QA-W2K16X64-1 at 5736.

VixDiskLib: VixDiskLib_Open: Cannot open disk [ESXi6.7] ESXI6.7-W2K16X64-1/ESXI6.7-W2K16X64-1-000002.vmdk. Error 1 (Unknown error) at 5813.

If I use a moref in the vmxSpec in 7.0, VixDiskLib_Open succeeds.

Was the ability to specify a vmPath in the vmxSpec deliberately removed in 7.0 or is this a bug that will be fixed?