Z axis drop on startup

Hello,

I have a Axyz Trident 4010 table with 7 tool ATC.
Occasionally upon startup the router, Oscillating knife, and Tangental knife all fall to the table.
All of this happens between the time i turn the machine on, and the console begins its booting process.
everything returns to normal once I instruct the machine to seek home. The machine continues to run fine for weeks afterward with little to no errors. this issue has happened twice now, and im concerned it is foreboding a larger issue.
Thnks,
Brent