System Lockdown in Allow Mode stops blocking / logging unapproved applications. You have a large number of file fingerprint lists added to the System Lockdown.
SEPM 14.3 +
By product design there is a limit of 64 file fingerprint lists that can be processed by System Lockdown. In current version there is no limit or warning message in SEPM UI to keep user from entering more than 64 file fingerprint lists.
Engineering is aware of this issue and UI fix will be released in the next product release.