This is a complete aside but my ex was the same. Her, ‘you should really do x.’ Me, ‘maybe, I’ll see how it goes/if I want/need to etc.’ Couple of weeks later, her, ‘I thought you said you were doing x?’ Me, ’no, you said I was doing x, I said nothing of the sort.’ It drove me mad.
Also another one that goes hand in hand very closely: Her, ‘I need to get an x because I’ve got to do y.’ Me, ‘you can borrow my x if you like, save you buying one.’ Her, ‘are you sure?’ Me, ‘yeah it’s fine.’ Couple of weeks later, me, ‘can I have my x back please?’ Her, ‘I thought you said I could have it?’ Me, ‘no, I said you could borrow it to save you buying one to do y.’ Her, ‘but I thought you said I could have it, you said it was fine.’ Me, ‘I said it was fine for you to borrow it, not to have it. Why would I say you could have it when I need it?’ And around and around we go until she gave it me back and I somehow felt like I had misremembered or was being unfair.
It’s subtle gaslighting, because it always leaves you feeling like you’re somehow being unreasonable or in the wrong.