Yeah, I don't believe it either, b/c it would not have been formed gyno. lol It simply does not happen that quickly. I have some pre-existing gyno, and it will feel as though it is getting thicker, and I will get a bit of puffiness around the area, but within hours of taking some AI it's back to the pre-existing amount that was there originally. If I were to leave it be for a couple weeks I'm sure it would add to it, but first, your initial shot takes time to peak. I know Sust has some prop, but still, E follows T.
LGD is known for causing gyno, but even still I never bother with Sarms when there are perfectly good anabolics, like, well take your pick, kicking around. I'm not calling you out, but it just doesn't happen that quickly. More than likely you had a tiny bit of pre-existing gyno and it began to flare up, which is why you should always keep an AI on hand.