Build Board disappearing.

Howdy All!
If you could all be so helpful to maybe explain or try and help me work out something.
I was building a house with a friend. We had the build board up for the house for about 3 minutes turning away to get the rest of the materials only to turn back and the build board to have vanished with 25 nails and 15 plained boards in it.
I know that build boards disappear after a period of time, but not after less than 4 minutes.
Could you maybe help clear up this predicament, please? After all the work getting the nails and boards, also the ground level enough for the house it is quite annoying as you could probably guess....
Any suggestions would be great. Thank you!
If you could all be so helpful to maybe explain or try and help me work out something.
I was building a house with a friend. We had the build board up for the house for about 3 minutes turning away to get the rest of the materials only to turn back and the build board to have vanished with 25 nails and 15 plained boards in it.
I know that build boards disappear after a period of time, but not after less than 4 minutes.
Could you maybe help clear up this predicament, please? After all the work getting the nails and boards, also the ground level enough for the house it is quite annoying as you could probably guess....
Any suggestions would be great. Thank you!