Incorrect timezones on new Teams and Outlook accounts

When adding new users to a Microsoft tenant, it seems to be creating the users with Pacific time, giving incorrect working hours on Teams and causing issues with Outlook calendar events

Connect from a non-admin PS prompt:

Import-Module -Name ExchangeOnlineManagement
Connect-ExchangeOnline

Check time-zones for all users:

Get-Mailbox | Where {$_.RecipientTypeDetails -eq "UserMailbox"} | get-MailboxCalendarConfiguration

Check timezone for single user:

Get-MailboxCalendarConfiguration -Identity $emailAddr

Set the timezone for a user:

Set-MailboxCalendarConfiguration -Identity $user -WorkingHoursTimeZone "GMT Standard Time"

Changes take effect fairly quickly.