Yes it's VERY strange! I'm wondering if it is the GD3B or even a faulty unit? Everyone has praised the GD3A it was what peeked my interest in GS-Audio in the first place! Also, "Tonytex" confirms its his new $100 benchmark and he is a VERY experienced reviewer who has reviewed & owns 90% of iem's under $300, he also owns 5 or 6 more expensive GS-Audio monitors and still says the GD3A is one of his favorite's! Check out his YouTube channe? He goes under the name "Akros" maybe you could have a chat with him or RikudouGoku to try and narrow down if its the GD3B or a faulty unit? although rare these things do happen, Tonytex's ST4 had an issue with one of the drivers which and he's waiting for a replacement.
Hope this helps?