sp_Blitz Findings: SQL Server Last Restart is an hour before Server Last Restart
I would 'suggest' that when the server was restarted (and Sql Server was also restarted) back on February 11, 2017, the current Windows time, which was Standard time and not Daylight Saving time, was captured as the Creation Date of TEMPDB (and that is what SP_Blitz uses to determine Sql Server restart time).  

Now, you are running SP_Blitz AFTER the change to Daylight Saving time and sys.dm_os_sys_info (which is used by SP_Blitz to report Server Last Restart and appears to be Daylight Saving time aware) is affected by the time change, thus making it 'look' like the server started AFTER Sql Server.