So basically #OpenBSD uses "0x0xCAFEBABE" (actually it requires 0x30784341464542414245 to connect) as the ESSID when it's actually "0xCAFEBABE".
I think i'll have a chat later on IRC, i dunno if it's a bug or some kind of security feature 
@julianaito @stsp may know, but I suspect it may be due to the remote nwid being a hex string, rather than actually hex.
@julianaito @stsp I mean, ifconfig 'nwid' supports both text string and hex up to 64 digits (denoted by 0x prefix). It seems your AP is using a hex string encoded as ASCII.
For example, "helloworld" could also be represented as 0x68656c6c6f776f726c64.
I see, so that behaviour is considered as normal (and it's not a big deal to be honest). I need to be more careful while reading manual pages !
@julianaito I had to double check myself, wireless terminology can be confusing. 
@stsp
@canadianbryan @julianaito I believe this behaviour predates my involvement in the wireless stack so... 🤷
@canadianbryan @stsp
Yes, it works as expected if i change the nwid to "helloworld" - as any network reported by "ifconfig iwn0 scan".
I tried to reproduce this "problem" with another device, the same thing happens.
I can provide more data if needed :)