I thought it might be important to confirm package versions.  Here is some
sample commands and their output:

before guix package -i pinentry (pass not giving pinentry prompt)

$ ls -l $(which -a pinentry)
lrwxrwxrwx 1 root root 71 Dec 31  1969
/home/zacchae/.guix-home/profile/bin/pinentry ->
/gnu/store/3hl7w63q0axngysrslkdw2a6jmgnm8kf-pinentry-1.2.0/bin/pinentry

after guix package -i pinentry (pass works normally)

$ ls -l $(which -a pinentry)
lrwxrwxrwx 1 root root 71 Dec 31  1969
/home/zacchae/.guix-home/profile/bin/pinentry ->
/gnu/store/3hl7w63q0axngysrslkdw2a6jmgnm8kf-pinentry-1.2.0/bin/pinentry
lrwxrwxrwx 1 root root 71 Dec 31  1969
/home/zacchae/.guix-profile/bin/pinentry ->
/gnu/store/3hl7w63q0axngysrslkdw2a6jmgnm8kf-pinentry-1.2.0/bin/pinentry

So it's not as simple as a version mismatch.

-Zacchaeus