There is no requirement or expectation for an aircraft to be in the envelope for any given loading you might start with - the requirement is that you MAKE it end up in the envelope. This might require
(a) reloading to suit
(b) a bit of temporary ballast in the nose or the boot for a problem this flight
(c) a bit of permanent ballast in the nose or boot if the problem is a continual pain in the neck
(d) there is no necessary reason for a given Type/Model to exhibit the same problems - all depends on the starting empty weight and CG and that depends very heavily on the specific aircraft's configuration and the sort of kit it might have fitted.