guix git authenticate throws hard

[jgart]

 guix git authenticate 95620d8845a75c9721876441e66bf28ba4a95eff jgart
Backtrace:
          11 (primitive-load "/home/jgart/.config/guix/current/bin/g…")
In guix/ui.scm:
   2263:7 10 (run-guix . _)
  2226:10  9 (run-guix-command _ . _)
In ice-9/boot-9.scm:
  1752:10  8 (with-exception-handler _ _ #:unwind? _ # _)
  1752:10  7 (with-exception-handler _ _ #:unwind? _ # _)
  1747:15  6 (with-exception-handler #<procedure 7f89c0e3bf30 at ic…> …)
In guix/channels.scm:
   164:10  5 (_)
In guix/base16.scm:
     71:7  4 (_ "a")
In unknown file:
           3 (string-fold #<procedure 7f89c0e3d4a0 at guix/base16.s…> …)
In guix/base16.scm:
    76:31  2 (_ _ 0)
In ice-9/boot-9.scm:
  1685:16  1 (raise-exception _ #:continuable? _)
  1685:16  0 (raise-exception _ #:continuable? _)

ice-9/boot-9.scm:1685:16: In procedure raise-exception:
In procedure bytevector-u8-set!: Argument 2 out of range: 0

WDYT