MS Teams - Multi-Client Login Issue

Question

Hi all, I'm hoping for some guidance on the issue described below.  It is causing issues for our users when they schedule a Teams meeting from Outlook or when they join a Teams meeting.

Scenario:

• Company A purchased Company B.  Both have MS Office 365 (Cloud) and Teams accounts for their users.
• Company B has completely migrated Office and Exchange accounts to Company A meaning they log in to all office products with their new ******@companyA.com email addresses.
• However, legacy Company B users are still using their Company B issues laptops with their Company B issues AD credentials.

Issue:

• Legacy Company B users are advised to sign out of Teams and sign back in with their ******@companyA.com email address so that it aligns with their new Company A outlook.
• If users restart their laptops ann they launch Teams, it is auto-logging them into their legacy Company B accounts.
• They then have to log out and sign in with their Company A account.

Workaround (kind of):

• Ensure all Office programs are logged into Company A accounts
• Cleared all credentials in credential manager
• Cleared all Teams cache from %appdata%/microsoft/teams
• This seems to stop the auto-login to the Company B account after a reboot

Needed Solution:

• However, if I click sign out of teams, Teams closes and I get a pop up to sign back in with my Company B email address.
• I'm assuming this field is being pulled from AD  since we are logged into our laptops with our legacy Company B user IDs