[BUG] Rip Tick Loss When Refreshed by Ferocious Bite and extended with Bloodletting Glyph

[Bisonpasfute]

1. Current Behavior

1.1. Description

Refreshing Rip with Ferocious Bite after extending it via Shred/Mangle through the Bloodletting Glyph can sometimes result in the last tick of Rip missing.

1.2. How to Reproduce

1. Go to the Argent Tournament Grounds.
2. Find a melee training target (e.g., NPC ID 33229).
3. Build 5 combo points using Cat abilities.
4. Use Rip.
5. Build 5 combo points using Shred/Mangle.
6. Cast Ferocious Bite as close as possible to a Rip tick (e.g., at ~10.2 seconds remaining on Rip).
7. Use Shred/Mangle three times to extend Rip.
8. Count the total number of Rip ticks after Ferocious Bite.
9. Observe that Rip only ticks 11 times instead of the expected 12.

1.3 Source Material

Bugged Behavior (Only 11 Ticks After Refresh):

• 11 Ticks After FB - Bloodletting Glyph Applied
  • In this case, Rip expired at 00:32.536, but the last tick occurred earlier at 00:31.998.
• 11 Ticks After FB - Bloodletting Glyph Applied (Logs of the Video) (Video Evidence)
  • In this case, you can observe:
    • Ferocious Bite at 01:47.709.
    • Next Rip Tick at 01:47.709.
    • Last Tick at 02:07.875.
    • Only 11 ticks of Rip.
    • Rip fades at 02:09.707.

2. Expected Behavior

2.1. Description

After refreshing Rip with Ferocious Bite via the talent Blood in the Water, and extending it through the Bloodletting Glyph, a Rip should consistently tick when fading.

2.2 Source Material

Normal Behavior (12 Ticks After Refresh):

• 12 Ticks After FB - Bloodletting Glyph Applied

[NerdEgghead]

This bug seems to be batching-related, and likely shares the same root cause as the "Ignite vomit" behavior exhibited by the Firelands 2pT12 set bonus. Our hypothesis for the cause is that the server stores an incorrect value for the remaining tick count on Rip whenever a Blood in the Water refresh occurs just before a tick, because that value is cached at the time of the Ferocious Bite cast, even though there is an aura update delay between the Bite cast and the Rip refresh. This then results in a math error when recalculating the refreshed Rip's expiration time, similar to the math error that can cause rolled over Ignite ticks to use the wrong damage value under similar circumstances.

It's worth noting that this bug occurs fairly infrequently during normal gameplay, since it requires an unlucky timing of your Ferocious Bite cast just before a Rip tick. As a result, while fixing this would of course be nice, it is far less impactful than fixing the Attack Power blocker on Rip refreshes (which affects every single Feral Druid's gameplay experience on every single boss fight):
#1571