The errata is not a specific vs general though. It's errata meant to clarify or change how the rules work. In this case, changing what is considered magical to bypass resistance and immunity. So in other words, it's changing how the general rule works. I don't understand why you're bringing up specific beats general in this context. There is no specific to trump the general rules when talking about the errata and GFB. The spell worked the same way before and after the errata. You made an attack granted by a spell, it has a spell source: It bypasses resistance and immunity regardless of other factors UNLESS something specifically states that it would not follow the general rules for bypassing. For example, if the general rule was that blue = 2 and you have a spell that says blue = 1 for the purposes of the spell. That's specific vs general and specific would win. If errata later clarified that the general rule is actually blue = 2 and/or 3, that's not specific vs general. That's errata meant to change how the game works as a whole.
You're also confusing 2 different topics of discussion. The weapon damage or type (blunt, slashing, piercing, fire, lightning, etc..) is also irrelevant to figuring out if the attack can bypass resistance and immunity. All that matters is the source of that attack (spell, item, magical sources). The errata does not look at damage, it looks at the source of the attack which allows the said attack to bypass. You're adding things into the discussion which aren't relevant.
Well agree to disagree I guess? I mean you're basically saying that anyone who doesn't agree with you isn't following what you call "standard logic and syntax". Kind of hard to have a discussion if you're going to insult your audience. However, I still assert that you're incorrect for the reasons in my previous post and this one. I would also strongly recommend you not fall into the "language syntax and grammar says x" routine because it's a discussion non-starter.