Windfury proc rate completely incorrect/not procing almost at all

[SirMilidan]

for the past month ive been playing enh shaman and the proc rate for windfury imbue is definetly incorrect currently.
im making some combat logs to show my case, but usually it takes at worst maybe 5-8 swings to see it proc at least once, where here its taking as long as 20 to even 40 in some cases.... please take a look at why this is happening

[SirMilidan]

i did some more testing., when i use rank 1 windfury imbue, it seems to be working perfectly.... but rank 2 is completely bugged.