Also noticed a modal messagebox popping up regularly when having kmail running.
Below is a workaround that simply always answers the question with no instead
of asking.
--- gnupg2-2.2.43.orig/agent/trustlist.c
+++ gnupg2-2.2.43/agent/trustlist.c
@@ -687,6 +687,9 @@ agent_marktrusted (ctrl_t ctrl, const ch
if (!nameformatted)
return gpg_error_from_syserror ();
+ // We do not trust this. Do not show that dialog.
+ return gpg_error (GPG_ERR_NOT_TRUSTED);
+
/* First a general question whether this is trusted. */
desc = xtryasprintf (
/* TRANSLATORS: This prompt is shown by the Pinentry
