Hello.
I have few data, but I have tested this in a few matches now(BG'S) and it seems the proc is not instant.
It seems unstable also. It is vital that the proc goes off instant and hit's enemy faster.
Never tried fear. Usually people use elemental drain for minor magic steal. Post patch debilitate will work.
Looking for any guildies I used to play with:
Havoc Warhammer - Alair
LoC EQ2 - Mayi and Iskiab
PRX and Tabula Rasa - Rift - Iskiab
Or anyone else I used to play games with in guilds I’ve forgotten