Hi,
Yes, LDK detects the tampering in system time.
If user tries to set the date back to some old value then the license will be disabled unless the date is set back to current value and is still under the validity period of license.
The time related errors (HASP_TIME_ERR or FEATURE_EXPIRED) will be returned only for time based licenses and not for perpetual.
For more details, please create a ticket on our customer portal https://supportportal.gemalto.com/csm
Regards,
Ashish