After accidentally coloring my Shulker Box to white color, and putting it on the floor caused the Shulker Box to respawn, and items inside despawning totally.

I tried immediately reproduce it by coloring another shulker and leaving only 14 andesite in it, didnt happen again.

I was playing offline alone, Im posting a link to a capture of the situation, sorry for the audio over, I was listening to some video.

https://www.youtube.com/watch?v=_75uk3v34Mg

0:20 is where it happens.