this sounds very weird but its true

i have a routerboard 433ah and a rb333

i have in my winbox the mac address for my rb433ah which i log into all the time
today i connected my old 333. i looked on the back at the mac address sticker and the macs are the same as those of the 433ah

what is going on here?

wait, the stickers are identical? or the MAC on the sticker of the 333 is the same as in the Winbox scan of the 433? Maybe you have some interesting setup, that makes it find the other Mac instead?

the stickers were different but both routerboards had identical macs.

i reset the macs both by doing /interface ethernet ether1 reset mac command on all interfaces and on both.

now they are ok ... they have different macs

Have you loadet a backup or so on to them?