Why InfernoStart/InfernoEnd last longer than FireGrenadeStart/FireGrenadeEnd

[JobberRT]

func (p *Parser) fgs(event events.FireGrenadeStart) {
	fmt.Printf("[%d] [%d] FireGrenadeStart\n", p.tick, event.GrenadeEntityID)
}

func (p *Parser) fge(event events.FireGrenadeExpired) {
	fmt.Printf("[%d] [%d] FireGrenadeExpired\n", p.tick, event.GrenadeEntityID)
}

func (p *Parser) is(event events.InfernoStart) {
	if len(event.Inferno.Fires().Active().List()) > 0 {
		fmt.Printf("[%d] [%d] InfernoStart\n", p.tick, event.Inferno.UniqueID())
	}
}

func (p *Parser) ie(event events.InfernoExpired) {
	if len(event.Inferno.Fires().Active().List()) == 0 {
		fmt.Printf("[%d] [%d] InfernoExpired\n", p.tick, event.Inferno.UniqueID())
	}
}

## Output
[82] [369] FireGrenadeStart
[82] [8845688937074081502] InfernoStart
[532] [369] FireGrenadeExpired
unknown grenade model 6670343291075039457
[1006] [375] FireGrenadeStart
[1008] [7320717329584455104] InfernoStart
[1359] [375] FireGrenadeExpired
[1363] [8845688937074081502] InfernoExpired

CS2 fire grenade last about 7 seconds(the duration that will do damage), which means FireGrenadeStart/FireGrenadeEnd get it right. But the comment says some demos don't include FireGrenadeXXX events and recommend to use InfernoXXX, so I tried InfernoXXX, but its duration is too long. Does Inferno include the particle effects after the fire is closed? How can I get the real burning duration in InfernoXXX?