I have the same problem. A password cannot be found... search won't find it, and browsing does not reveal its existence.
This seems to happen when I accept LastPass' dialog to add a password to the vault
It also happens every time I modify the "Name" field of a password
I am using Chrome, and logged into My LastPass Vault as Family Manager
Click the wrench icon to edit a password
Change the Name field
Green "Success" banner appears at top of My LastPass Vault
search for the new name...
! your password is not found !
I usually then close the browser window and open a new one, then open My LastPass Vault, and the password is there.
I have also found that clicking around inside the vault to look at other areas like Addresses or Notes will address the issue. When I return to Passwords or All Items, the renamed password is visible.
So it is not a serious bug, but a disconcerting one that makes me lose confidence in the product. I am putting much faith and trust in LastPass. I need it to be bulletproof and reliable.
Please fix or provide a work-around. I want to trust LastPass