pass init does not re-encrypt existing files

[Frank Thommen]

Hi,

In an attempt to use pass for a shared password store @work I tried the 
instructions given on 
https://medium.com/@davidpiegza/using-pass-in-a-team-1aa7adf36592. 
However even after importing a colleagues' public gpg key, signing it 
and applying `pass init id1 id2`, existing entries could still not be 
seen by him:

$ pass a/b
gpg: decryption failed: No secret key
$

Entries created *after* the additional `pass init` could be read by both 
users, but not those created beforehand.

We are using pass 1.5 on CentOS 7 (from EPEL).  GPG is version 2.0.22.

I'm grateful for any hint on how to re-encrypt also existing files.

Cheers
frank