-Confirmed-
I am able to reliably reproduce this affect 100% of the time by simply putting items into the cargo block and pulling them out again.
Steps to reproduce:
Put items into cargo block
Re log, because it doesn't update for some reason (If this isn't the case for you skip this step or you may not have the bug)
Once you have re logged, Pull them out again and you will see that the cargo is still there.
Seems to fix itself via relog
Tested on 0.19541