Have noticed LastPass draining my battery (Pixel 3a) in last few days. Have shut off background usage. No other apps come close to. Google is at 10% however I'm using that ten times an hour and use LastPass on phone maybe once a day.
Our development team is aware of battery drain issues on Android and are actively working to resolve the issue in a future update. While we don't yet have an ETA for an update, as a workaround in the meantime, disabling background activity for the LastPass app from Settings has should help to reduce battery usage.
So that our team can gather more details and hopefully resolve this issue as soon as possible, could you submit a bug report following the steps here? https://support.logmeininc.com/lastpass/help/how-do-i-report-a-bug-to-lastpass
I have had this issue twice on my LG V60 (huge battery usually lasts 2-3 days between charges). Both times suddenly I was running out of juice in less than a day and when I checked battery usage LastPass was at the top of the list with >50%. The first time I uninstalled LastPass and lived without it for a few weeks before reinstalling it. The problem did not reappear immediately, but it took 2 months before reappearing (today).