It's irrelevant since, as in the link:

Protocol III states though that incendiary weapons do not include: ... Munitions designed to combine penetration, blast or fragmentation effects with an additional incendiary effect, such as armor-piercing projectiles, fragmentation shells, explosive bombs and similar combined-effects munitions in which the incendiary effect is not specifically designed to cause burn injury to persons, but to be used against military objectives, such as armoured vehicles, aircraft and installations or facilities.

Having an incendiary mechanism doesn't mean it is an incendiary weapon in the sense of your quote of Section 6.2 of the 1999 UN Secretary-General’s Bulletin.