I've done that here: https://en.wikipedia.org/w/index.php?title=MediaWiki:Acct_creation_throttle_hit&diff=prev&oldid=1320393389

Just checked on enwiki, and the correct message is now shown:

In T409161#11340926, @Johannnes89 wrote:

In T409161#11339571, @kostajh wrote:

https://en.wikipedia.org/wiki/MediaWiki:Acct_creation_throttle_hit this message override needs to be updated to accept the parameter $2

This probably affects many other wikis as well. Checked the same message on my home wiki and realized we’re also using an override without the parameter $2
https://de.wikipedia.org/wiki/MediaWiki:Acct_creation_throttle_hit

Fixed the dewiki message, but there are indeed ~100 other wikis affected per https://global-search.toolforge.org/?q=%241&namespaces=8&title=Acct+creation+throttle+hit

Ideally there would be separate messages for regular accounts and temporary accounts:

• A separate message for TA wouldn't require updating the existing overrides which are still correct for regular accounts
• T357802: Design & Copy: Prompt user to create a regular account after temp account creation rate limit trip also requires a separate message for TA rate limit
• Customisations like enwiki pointing to https://en.wikipedia.org/wiki/Wikipedia:Request_an_account only make sense for people trying to create a regular account
• Even the message on translate wiki only mentions "accounts" which might be confusing because logged-out users didn't attempt to create a (regular) account

Let's follow up on this in T407653: Messages such as acct_creation_throttle_hit and wikimedia-acct_creation_throttle_hit are hard to translate.