Duplicate Blank nicknames

[adorluigi]

What type of bug are you reporting? Mechanics

What is the bug?
https://replay.pokemonshowdown.com/gen9anythinggoes-2278371586-oc6gpem59vi2gq0lyrt4r0ekiedila3pw
normal AG ladder game, turn 7 the chat starts spewing errors and the miraidon on turn 8 didn't activate its ability
guessing something to do with the pokemon names cause nothing even shows up in the name slot when you inspect element

Are you able to replicate it? If so, how?
I tried to reacreate to no avail

 

[urkerab]

I can confirm that the chat error is caused by the missing name (the chat log is trying to process the leech seed damage on the Arceus but can't work out which Pokémon is damaging the Arceus); this causes the identifier to be p1a: which fails to parse because there's no space after the :.

 

[DaWoblefet]

The correct fix should be server-side here; the server should not be sending over blank nicknames. I assume this was some obscure UTF-8 character; when I check the corresponding inputlog, the nickname is just blank there, and the particular character does not appear to be stored.
Edit: this is a duplicate of https://www.smogon.com/forums/threads/zero-width-unicode-characters-in-nicknames.3735286/