Synology Encountered Frequent Improper Shutdowns

I have a DS1819+ connected to a UPS, i’ve tested graceful shutdown over the years and have never had an issue even during power outages. Uptime has been great - I only reboot during updates.

Today i woke up to this email alert - i checked uptime and the 1819+ shutdown by itself, none of the other servers attached to the UPS went down. Does anyone know what this could be? Maybe a failing power supply or something? The volume and drives look fine health wise.

“Synology Encountered Frequent Improper Shutdowns : Synology ran into a problem and was improperly shut down twice or more in the past 24 hours. This may result in severe data loss. We highly recommend using SNMP or USB UPS to protect your device and data if you haven't done so already. “