Due to a problem in the Quartus® Prime Pro Edition Software version 21.3 and later, you might see incorrect results in the Timing Analyzer Datasheet Report.
This problem only affects the Datasheet Report and does not affect the default signoff timing or any reports other than the Datasheet Report.
To work around this problem, disable multicorner support for Timing Analyzer in Assignments > Settings > Compilation Process Settings.
Alternatively, add this .qsf (Quartus® Settings File) setting
set_global_assignment -name TIMEQUEST_SIMULTANEOUS_MULTICORNER_ANALYSIS OFF
This problem is scheduled to be fixed in a future release of the Quartus® Prime Pro Edition Software.