Same here! When I have just created or updated a password, the Chrome extension puts out the pop up asking if I would like to add or update, respectively, but clicking it just opens up another pop up that says "Invalid Response" and no changes are saved. The same message is given when I try to add or update from the Chrome extension Vault but I can add or update normally by going through the actual Last Pass website to get to my vault.
If I inspect the page (using Chrome developer tools), clicking the "add" or "update" buttons outputs the following message to the Console:
"Cannot read property 'getFormMetaData' of undefined contentScriptSiteDialog.js:1"
Trying again, I got these messages instead (I was testing with my Dropbox account):
"WebSocket connection to 'ws://127.0.0.1:17602/ws' failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED pkg-unity.min-vflmDmeP5.js:1"
I could not get any errors to show in the Console when trying to submit from Chrome extenstion Vault.
Actually, I could not get any more errors in the console, even when I was submitting to the pop up.
One more issue I noticed is, when I went and changed my password in LastPass website vault, the Chrome Extension would not get the update and would still fill the old password.