bug#58309: [BUG Report] found a bug? followup

[Frank Pursel]

Performed another 'guix pull' to receive one more change which led to
the additional reporting:

guile-ssh-0.15.1-debug  238KiB 227.0MiB/s 00:00 [##################] 100.0%
Backtrace::
          15 (primitive-load 
"/gnu/store/k76q0ikk8a7769b0d2b9y3jj2mpaywh0-compute-guix-derivation")
In ice-9/eval.scm:
    155:9 14 (_ _)
    159:9 13 (_ #(#(#(#(#(#(#(#(#(#(#(#(#(#(#(#(#<directory (guile-u?> ?) ?) ?) 
?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?) ?))
In ice-9/boot-9.scm:
    152:2 12 (with-fluid* _ _ _)
    152:2 11 (with-fluid* _ _ _)
In ./guix/store.scm:
  2165:24 10 (run-with-store #<store-connection 256.99 7f657621c140> 
#<procedure 7f656de87c80 at ./guix/self.scm:12?> ?)
   1993:8  9 (_ #<store-connection 256.99 7f657621c140>)
In ./guix/gexp.scm:
   300:22  8 (_ #<store-connection 256.99 7f657621c140>)
   1181:2  7 (_ #<store-connection 256.99 7f65668495f0>)
   1047:2  6 (_ #<store-connection 256.99 7f65668495f0>)
    893:4  5 (_ #<store-connection 256.99 7f65668495f0>)
In ./guix/store.scm:
  2050:12  4 (_ #<store-connection 256.99 7f65668495f0>)
  1402:13  3 (map/accumulate-builds #<store-connection 256.99 7f65668495f0> 
#<procedure 7f65618e48e0 at ./guix/stor?> ?)
   1398:5  2 (map/accumulate-builds #<store-connection 256.99 7f65668495f0> 
#<procedure 7f656a61b840 at ./guix/stor?> ?)
  1414:15  1 (_ #<store-connection 256.99 7f65668495f0> 
("/gnu/store/063db2n6gr2pqvy77fxp82p0ki6vwklz-guile-avah?" ?) ?)
  1414:15  0 (loop #f)

./guix/store.scm:1414:15: In procedure loop:
ERROR:
  1. &store-protocol-error:
      message: 
"`/gnu/store/njq3x65m5zc2kwynswzmpc3nfwcwnp15-guix-1.3.0-29.9e46320/bin/guix 
substitute' died unexpectedly"
      status: 1
guix pull: error: You found a bug: the program 
'/gnu/store/k76q0ikk8a7769b0d2b9y3jj2mpaywh0-compute-guix-derivation'
failed to compute the derivation for Guix (version: 
"fd6cd9de8682c7ddf96bf8deb637b1ca6cdbd205"; system: "x86_64-linux";
host version: "e6777cfa5eb5e9c36eaf7810b42cac0fbcaa367c"; pull-version: 1).
Please report the COMPLETE output above by email to <bug-guix@gnu.org>.