We've seen players ask about this before, and have some clarification for you from Jason Attard (Senior Game Balance Designer):
This behavior was unintended, but we do not consider it an exploit. We do intend to make reverse engineering more consistent in the future, and that may be by not allowing this or by allowing players to reverse engineer this type of mod by design. We do not consider this a violation of the rules.
Thanks for the clarification that it's not an exploit. It can be stressful when you find something out like legacy smuggling or REing other crafters mods and you find yourself going, "uhhh, is this a cool trick or a cheat?"