Yes, I believe the FD thing was a problem that the PMBR is/was working on. Hopefully, it's fixed.
Edit: More on the tumble thing. There are additional exemplary situations that show that being in the neutral air state is better than being sent into tumble. For instance, consider the situation where a character is standing at the edge of a platform. If that character's shield is hit so that he slides off the platform while facing towards the edge he slid off of, he will fall normally, as if he had just walked off, and will be able to do whatever in the world he wants. He can jump, attack, AD, or just land with his 2 frames of landing lag and be on his merry way. So if he wanted to, he could AD to avoid his opponent's follow-up (or waveland) or he could just land and perform some countermeasure on the ground to protect himself or gain better positioning.
Now, if that character's shield is hit so that he slides off the platform while facing away from the edge he slid off of, he will enter tumble. That character's actions are now MUCH more restricted. He can still jump and attack, but he can no longer AD to avoid the opponent's follow-up, and if he lands, he is forced to either tech or enter hard knockdown. As you can imagine, this is greatly beneficial to the opponent as he now gets a free tech-chase. Jumping out of tumble puts one at risk of being caught without their double jump (DJ), causing juggles, and attacking forces you to land with landing lag. All of those are usually worse than just landing or wavelanding (with an AD).
What is the moral of the story? It's practically always better to be sent into the neutral air state than into tumble and if something about being sent into the neutral air state is causing you to SD accidentally, then I suggest that you become aware of and comfortable with all the situations that cause you to be put into that circumstance. It's much better, from a competitive standpoint, to just get better at certain aspects of the game, which can actually be useful, than to change them needlessly.