well some time ago when i was playing l2mafia i found 2 way's of augument stucking.
1st - is with burning weapon with augument skill
Wear weapon on what you have augument skill, enchant it till it burns. after that you will see that skill have been stucked.
here i burned that weapon with skill and skill have been stucked
2nd - is going in oly.
as some mafias player know when you go in oly in mafia most of augumented and simply weapons wears off when starts buffing time. at the moment when augumented weapon wears off augument skill stucks. so before you go in oly wear weapon on who ar skill what you realy need in oly ( example shadow flare lvl10 ) and when that weapon wears off take youre fighting weapon and you still have shadow flare in skills.
P.S. both type of stucking works till rr or sub change