for me it was switch pro, and why i outright have a grifter on this forum blocked because they used it to pump their podcast and then acted like it was just plans changing when it didnt come true, lol
but yeah that in general just made me fully tune out of... pretty much every ninty rumor? i seldom believe many of them anymore unless a rating board or something leaks it out.
though with you mentioning Andy, that also reminded me that VGC is usually another outlet I ignore rumors from now, since they seem to lean very heavy on the tabloid aspect to push anything even if it's super flimsy. Still not over them running articles off of shitty translations as if they were fact (only for JP speakers to later point out that no, the machine learning they quoted was nothing like what was really said)
But yeah, Switch Pro and the whole PS Plus program hype were the two biggest burns for me. And like, PS Plus did happen, but when certain people were boasting of dozens or hundreds of PS1 games being made ready for it, and the reality ended up being a slim amount of poor PS1 ports, lots of shitty PSP games, and the PS2 getting fully ignored... Yeah, that somehow was even lower than my already low expectations for what Sony would likely do with that Premium service.
Before the Switch era got really into swing, the big rumor i also fell for and hated having not come true was the GCN ports on Switch rumor. I was so adamant about it, I literally bought my system on launch day primarily thinking Melee or Animal Crossing would hit the eShop any day now and the VC was just taking a while like it did on Wii U. I ended up binging Soldam, BMZ and Bomberman R as my launch month titles with giving Zelda a try instead (and even now that Pikmin 1/2 straight ports show that they will make GCN ports on switch now, I am convinced that rumor of Melee/Luigi Mansion/Animal Crossing coming to Switch was total bull.)
Oh well. Mario Odyssey would have been when I would have bought the Switch no matter what anyhow and I got to play a lot of great games come June so a 3 month drought before I started playing the system on a daily basis wasnt too bad for me