Aziraphale's memory, Jimbriel, the Metatron, and forgiveness
There's a bit of fanon that goes like, Crowley can't believe Aziraphale loves him even were Aziraphale to say so, because Aziraphale is an angel and angels love everyone.
S2 kind of explodes that one. (Which, I mean, continue to use it if you like; fanon is fanon and getting jossed happens to the best of us.)
Not long after his arrival in the bookshop, Jimbriel says to Aziraphale, "You're funny. I love you."
"Oh. Thank you," says Aziraphale, with just a tiny bit of gratification even. And then he says "I..." and can't finish the sentence. He can't return the sentiment with I love you too. He remembers too much, and isn't ready to forgive or forget, much less love.
His reticence gets followed up on during the Job minisode. "You were awful once," he tells Jimbriel flatly. "Really, really awful." Notably, he's not saying this because of Gabriel's treatment of him -- but because of Gabriel's role in Job's story.
I don't think Aziraphale's opinion of Jimbriel -- a lorge nuisance who used to be a horrible clueless purveyor of cruelty -- shifts until the demon attack on the bookshop. Before Jimbriel goes out to Shax, Aziraphale doesn't protest that Jimbriel is too -- too anything, too valuable or too angelic or too important -- to save. He falls back on his own guardian role, telling Jimbriel that he said he would protect him (did he? did he, actually? I'm not sure he did) so he will.
Jimbriel tells him there's no need, he's going out -- and we get quite a long shot of Aziraphale's face, which reads to me as both surprised and somewhat unwillingly impressed. Aziraphale can respect self-sacrifice.
I think this is why he gives Gabriel and Beez their way, deferring to their wishes. He's learned that with a little Jim and a dash of love for seasoning, Gabriel won't be awful, and he's willing to trust that... and forgive what he can of Gabriel's derelictions.
Now then.
In season 1, a desperate Aziraphale approaches the Metatron to beg him to save the world. The Metatron brushes him off in the cruelest way possible. He's Gabriel -- but worse, because he's not clueless, he seems to know exactly what a nuclear exchange is and the devastation it will cause, he just doesn't care. We can see Aziraphale's heart breaking, right there onscreen.
I'm on record multiple times thinking that Aziraphale is not taken in by the Metatron, or the Metatron's coffee, or the Metatron's job offer, or the Metatron's offer of re-angeling Crowley, or any of it. This is another reason I think that. Aziraphale can hold a grudge, at least subliminally, and he's got one tall leftover grudge against the Metatron.
There's no reason at all for Aziraphale to think the Metatron has changed since Armageddon't. There's been no Jimbriel phase to change Aziraphale's mind. There is no apology from the Metatron. Coffee and job offers are no kind of atonement!
Crowley's memories may have been tampered with. Aziraphale's haven't. He knows what the Metatron is, and he knows perfectly well not to trust him. That's my story and I'm sticking to it.