Nylas syncs unexpected folders
When you authenticate an end user's Microsoft account, Nylas syncs all folders in the account. This might include several that aren't normally visible to end users.
Depending on the email account, Nylas might sync the following system folders:
AUDITS
DELETIONS
DISCOVERY HOLD
PURGES
SUBSTRATE HOLDS
VERSIONS
Nylas recommends you don't display the email messages stored in these folders, as it might confuse your end users.
For more information about these folders, see Microsoft's official Recoverable Items folder in Exchange Online documentation.