Important bug

I've found a bug that sometimes, on a restore, leaves a sprite lying on every scene, a sprite that cannot be picked up. I can't reliably reproduce it. I thought at first that if you started a new game and restored a situation in which you were carrying a sprite, then it happened, but it doesn't seem to be that. Ho-hum... The position it occupies on the restored scene and all other scenes is the same as its original (i.e. game start) position. Later (much later, days later) I stumbled upon the bug again and can now reproduce it. It happens if I put the key in the inventory, then exit the inventory and save. Then I enter the inventory and pick up the key and restore. Now I can reproduce it, it should be simple to fix!