[BUG] Hunter serpent sting duration

[SaengNyangiee]

1. Current Behavior

1.1. Description

serpent sting duration
When applying the serpent sticking pattern, the refill duration is 18 seconds with cobra shooting
If the serpent sting pattern is not applied, the duration is only applied up to 15 seconds, is this correct?
There is nothing written about duration in the tooltip

1.2. How to Reproduce

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1.3 Source Material

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2. Expected Behavior

2.1. Description

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2.2 Source Material

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[Pekafu]

This is probably intended.

When Serpent string dot is applied via "Serpent Sting" duration is 15sec. Cobra Shot gives 6sec extra duration to the dot. This seems to stack up to 18sec.