Issue with pinentry GUI agent

[sunrises at gmx.com]

Hi all, since some days I'm having an issue with pinentry, I've set the default agent as pinentry-qt4
from update-alternatives (I've also tried pinentry-qt and pinentry-gnome) but when I run gpg --decrypt file
it's always falling on the cli for prompting the password. In .gnupg/gpg-agent.conf as the first line I have 
pinentry-program /usr/bin/pinentry-qt4 as well, but I don't get why it's ignoring it.
There's a way to debug what's going on?