if u have SphereComponet, BoxComponet(let call it polluted zone)….. when your character move inside pollutedzone both BeginOverlap and EndOverlap event fire same time(move inside polluted and staystill inside zone normal) it may be u set your collision Enable:
(ECollisionEnabled::ECollisionEnable(Query and Physics)).
u should set it to
(ECollisionEnabled::QueryOnly(No PhysicsCollision)).
u also change it in editor (picture below)
select your box or spherecomponent(for me it call pollutedzone) that u want it overlap or end overlap with your character (remeber after u set it Query Only, it only fire overlap event for hit event not fire.