Thundering strikes talent does not work

[Quille 0]

Hello! I have recently changed specialization by my shaman (Bocowa) from Restoration to Enhancement and found out to my deep disillusionment that the Thundering strikes talent seems to be not working at all 😞 . As the description states it should improve my chance to get a critical strike with my weapon attacks by 5% (if 5 points are spent) but it doesn't increase my critical chance at all! Moreover, I have only 3.73% critical chance as my spellbook hint indicates. How is it even possible? Did I have -2% before I spent those points? Or Thundering strikes are broken? Or it just does not show the correct information? I appreciate any help, thank you!