GAS: OnTagUpdated() not called when calling SetLooseGameplayTagCount()

Context

AbilitySystemComponent has a virtual function

virtual void OnTagUpdated(const FGameplayTag& Tag, bool TagExists);

that gets called when a gameplay tag gets added or removed, so whenever a gameplay tag's count changes states between zero and non-zero.

Problem

A licensee has reported that this function is not called when setting a tag's count directly via

void UAbilitySystemComponent::SetLooseGameplayTagCount(const FGameplayTag& GameplayTag, int32 NewCount); 

while it does get called via other APIs like Add/RemoveLooseGameplayTagCount(). I confirmed both those observations.

Suggestion

SetLooseGameplayTagCount() should cause OnTagUpdated() to be called when the call causes the tag to change states between present and not-present.

• Create a native subclass UMyAbilitySystemComponent from UAbilitySystemComponent
• Override OnTagUpdated, print the tag name and put a breakpoint on there
• Give some actor a UMyAbilitySystemComponent
• In that actor's native BeginPlay call ASC->SetLooseGameplayTagCount(SomeTag, 1)
• Observe: OnTagUpdated is not called
• Expected: Because the count changed from 0 -> 1, OnTagUpdated is called

Non-fatal, just for reference: 

>    [Inline Frame] UnrealEditor-GASRepro53.dll!UAbilitySystemComponent::SetTagMapCount(const FGameplayTag &) Line 622    C++
     [Inline Frame] UnrealEditor-GASRepro53.dll!UAbilitySystemComponent::SetLooseGameplayTagCount(const FGameplayTag &) Line 687    C++