Please try the attached patch.
diff --git a/libmailutils/imapio/flags.c b/libmailutils/imapio/flags.c index b84f4fb..02a20af 100644 --- a/libmailutils/imapio/flags.c +++ b/libmailutils/imapio/flags.c @@ -34,7 +34,7 @@ _imap4_attrlist[] = { "\\Flagged", MU_ATTRIBUTE_FLAGGED }, { "\\Deleted", MU_ATTRIBUTE_DELETED }, { "\\Draft", MU_ATTRIBUTE_DRAFT }, - { "\\Seen", MU_ATTRIBUTE_SEEN|MU_ATTRIBUTE_READ }, + { "\\Seen", MU_ATTRIBUTE_READ }, };
static int _imap4_nattr = MU_ARRAY_SIZE (_imap4_attrlist);