Bar display of Thorim taunt count, shows when he is fully taunt immune after 5 taunts within the DR period (20 seconds). Bar counter should display 1-2-3-4-IMMUNE in sequence, before resetting after the DR expiry.
Taunt DR timer begins to count down when the taunt debuff expires from the target. Any taunt within the current DR timer will then reset the timer (again, upon debuff expiration).
Importantly, this means that while the taunt DR timer is always 20 seconds, the time between casting the 5th taunt and the DR immune period ending will be slightly longer. As of the most recent version, the WA timer is triggering from debuff expiry - you will see a delay between the taunt cast and the bar display, this is working as intended.
Only Triggers on Thorim, but can easily be repurposed for other encounters if it becomes relevant