Sudden crash upon save from terrarium

This has happened two times so far, 100+ day servers that suddenly crash upon the daily morning DST day save with the line at the bottom of the log: 

"[08:03:17]: Missing reference:    113714 - terrarium    ->    322203    nil" 

No other crash info in the logs except for this, as this is the bottom of the log at time of crash. I do not know what the issue might be 

closelog DST_SG 01_04_22.txt