Platform: Windows
Type of Internet Connection: DSL
Date & Time: Feb. 21, 2014 2:15a CST
Frequency: Always
Race: Mithra (Monstrosity Purbol)
World: Shiva
Main Job: WAR
Support Job: BLM
Level: 30 (capped)
Area and Coordinates: Buburimu Peninsula
Party or Solo: Solo Monstrosity
Monster Name: Any

In Monstrosity, when attempting to cast Stone II or any spell which has revised required MP in the February update, the wrong MP amount is consumed.

The spell list reflects the revised amount - For example, Stone II is listed as requiring 16 MP to cast. However, actually casting the spell in Monstrosity will still consume the old total, 36 mp.

Furthermore, if the Monster has lower than the old amount required to cast (Stone II: 36), but enough for the new MP cost (16), then the spell can be cast without consuming MP.

This is a little tricky to explain, so as an example:

(Stone II lists a cost of 16 MP)
Player Monster MP total: 500/500 -> Stone II consumes 36 MP
Player Monster MP total: 36/500 -> Stone II consumes 36 MP
Player Monster MP total: 16/500 -> Stone II consumes 0 MP