Why is my custom animNode casting to engine version?

Followed the tutorial here: Except I’m creating a AnimNode_SkeletalControl / AnimGraphNode_SkeletalControl. I chose to do a test with the TwoBoneIK function by creating a duplicate of it. So mine is only different in two areas that I can see. One I’ve changed the name of the text in the AnimGraphNode part to reflect my projects name so I can easily distinguish between it and the engine version. And Two, in my AnimNode header, where the structure is defined I use my project API

struct KORESHANTY_API FKoreAnimNode_TwoBoneIK : public FAnimNode_SkeletalControlBase

When I drop the animation node in the blend space in the editor and hook it up where there was the standard engine version before, once I hit compile in the editor window it crashes out completely and the output log says

“Fatal error: [File:D:\Build++UE4+Release-4.17+Compile\Sync\Engine\Source\Runtime\CoreUObject\Private\Templates\Casts.cpp] [Line: 10]
Cast of KoreAnimGraphNode_TwoBoneIK /Game/MixamoAnimPack/Mixamo_Goblin/Anims/MixamoAnimBP_Goblin.MixamoAnimBP_Goblin:AnimGraph.AnimGraphNode_StateMachine_6.Default.AnimStateNode_1.Locomotion/Idle.KoreAnimGraphNode_TwoBoneIK_0 to AnimGraphNode_TwoBoneIK failed”

It appears to be casting from my version of the KoreAnimGraphNode_TwoBoneIK to the engine version AnimGraphNode_TwoBoneIK . Why is this and how can I stop this from occurring?