Invigorate rank 3 and 4 skill not work

at first I thought maybe it does recover but I can't see it
after test it on friend we realize that skill is broken and no sp recover at all

I try using other staff with Invigorate II and it's work
not sure about other rank also broken or not though because I don't have one to try

Still not working. My friend is having the same issue.

Do you guys have the required mnd to actually cast the spell properly?

Rank II needs min 20 mnd, Rank III min 30 mnd, Rank IV min 40mnd, etc. If you guys don't have at least the min amount of required mnd then the skill is more likely to fail.