That’s not a foot print. The patter exactly follows the bubbles in the envelope. It just got dirty, and dirty in such a way that the dirt only contacted the slightly raised bubbles, so it must have come into contact rather gently.

And seriously, your drive packaging is not crushed, wouldn’t that have been you first hint that it had not been stepped on? Like, for comparison, put the drives back in the envelope, stomp on it with your foot, and compare the results.