There is one scenario when an Abnormal file is not automatically quarantined when Auto-Quarantine Abnormal Files is enabled. While this scenario is rare, this FAQ provides the reason why it could happen.
If a file was considered Safe, then the Cylance model is updated and the file is now considered Unsafe, Cylance Smart Antivirus will mark the file as Abnormal and not automatically quarantine the file. The Cylance model is the mathematical model used to analyze files.
The software program or file is analyzed by Cylance and is considered Safe. Because the file is considered Safe, it doesn't appear in your Dashboard. Then the Cylance model is updated and that same file is now considered Unsafe. If the software program or file is being used, automatically quarantining it could impact whatever you are doing. Instead, the program or file is being brought to your attention as an Abnormal file. You can then review it and determine if you want to allow it or quarantine it.
Why would the file now be considered Unsafe? Maybe the file was built using a program that shows potentially malicious behavior, or the certificate used to sign the file is suspicious. For whatever reason, the file is now considered Unsafe.
Why not quarantine the file if it's considered Unsafe? The file is being brought to your attention so you can review it and make a decision to keep it or block it.