A few days ago, I was printing a big model on my Ender 3 Max.
I have monitored the print for the first layers, prefect first layer.

Then I left to do some shopping.
When I came back after a few hours  to notice that spool had jumped off the holder.

Result one ruined print and a few days later the same thing happens when I was present.
I looked on the internet for a solution, did not find anything, so I fired up Fusion360 and created something that would prevent the spool jumping off.