As explained earlier in this thread, it is not difficult to implement, but there was a deliberate decision made in 2021 to make the save/update prompts active also when the vault is locked (this was in response to popular demand).
You do have the option to disable this behavior on specific websites by adding those domains to the Excluded Domains list, or you can fully disable the prompts for saving new logins and/or the prompts for updating new logins.
FYI, the feature request to enable the save/update prompts for locked vaults had 10 times as many votes as the current request (to disable the prompts), so this feature request will likely need significant community support before there can be any movement on considering development.