Create a ConvertTransformToRelative blueprint node. This was not supposed to be usable, as it was intended to be replaced by MakeRelativeTransform.
After applying this change, the old node should be replaced by MakeRelativeTransform (with input parameters swapped intentionally), and you cannot add the old node any longer.
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There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-172241 in the post.