Time drift detected. Please check VKTM trace file for more details in alert log file

Time drift detected. Please check VKTM trace file for more details.

Message in alert log file. Opening the database takes time

Follow below mentioned the note-id :
Time Drift Detected. Please Check Vktm Trace File For More Details. (Doc ID 1347586.1)

Download and apply patch 11837095 as available for your release/platform.
NOTE:
Patch 11837095 extends to functionality of event 10795 (set to level 2) for VKTM tracing and limits alert log entries.

After applying the patch, enable event 10975 at level 2:
alter system set event="10795 trace name context forever, level 2" scope=spfile;

After applying the patch the issue is fixed.

Below Warning can be ignored while applying opatch:
OPatch found the word "warning" in the stderr of the make command.
Please look at this stderr. You can re-run this make command.
Stderr output:
ld: warning: symbol '_start' has differing types: