Today, by checking my trust page, i found the notice that my email was recently changed to <...>@bounces.invalid

This is something we recently started doing. If email sent to your email address bounces with an error message like, "This email address doesn't exist", then your email may eventually be changed to u...@bounces.invalid. (It's not possible for users to change their email address to something ending in .invalid, so this can only be an administrative change.) Because your old email didn't exist, somebody could've registered your non-existent email address and used that to steal your account.

I didn't particularly intend for the trust warning to appear for these automatic changes, but it's a niche situation and a bit difficult to fix, so I probably won't fix this unless several other people complain. It only lasts 30 days, after all.

- My yahoo inbox was completely empty when i checked it today after almost 6 years since the creation date. This maybe due to some default settings because i checked another old yahoo email and all inbox folders are also empty.

Inactive mailboxes in Yahoo Mail

After 12 months or more of not using your mailbox, it is considered inactive. It will stop receiving new emails, and all mailbox contents, folders, contacts and settings are permanently deleted.