Hello @vikideblois​,
Welcome to the LastPass Community!
I was checking your account and I see you have enable the policy for auto-log off other devices. You will to turn it off by going to Account Settings > Show advanced settings > Security > Auto-log off other devices> untick the option and then hit update. You can find more about the option here: https://support.lastpass.com/s/document-item?bundleId=lastpass&topicId=LastPass/Automatic_Logoff.html&_LANG=enus#:~:text=Select-,Account%20Settings,-in%20the%20left
Kind Regards,
Alejandra
LastPass Support