Ridiculous errors from !uniqstack output

This has to be the most confounding thing I have seen with Windbg till date. I have a dump file which loads just fine on every version of Windbg. But on the specific Windbg version from Windows 10 SDK – v10.0.15063.137, my !uniqstack command spits out the following error for *every* thread with an unique callstack:

Requested number of stack frames (0xfffffff87dceaa87) is too large! The maximum number is 0xffff.
^ Range error in ‘~.;k -782315579’

Its the same error for every thread. However ~*kv works just fine.

Is this a bug?