i nowhere saw string "(%", it's error or it should be so?
file: /libmailwatch-core/mailwatch-net-conn.c
line: _("Buffer is not large enough to hold a full line (%" G_GSIZE_FORMAT " < %d)"),

imho "%d" is part of string, but in .pot file line looks like: msgid "Buffer is not large enough to hold a full line (%"