Common issues causing Actor Components to not work correctly.

Using EditAnywhere or BlueprintReadWrite on components

Components should not use EditAnywhere or BlueprintReadWrite. Instead, use VisibleAnywhere and BlueprintReadOnly.

UPROPERTY(VisibleAnywhere, BlueprintReadOnly)
UWhateverComponent* WhateverComponent;

Not initializing components in constructor

You need to use CreateDefaultSubobject in your actor constructor, or correctly initialize components at runtime

WhateverComponent = CreateDefaultSubobject<UWhateverComponent>("WhateverComponent");

Using spaces in component names

Do not use spaces in component creation. This has been known to cause random issues.

WhateverComponent = CreateDefaultSubobject<UWhateverComponent>("Dont put spaces here");