You should vs human nature. We introduce bugs. Please don't be cynical, and cheer this up.
Kudos to facebook team that they responded shortly, I cannot tell if it was work hours or not, but either way, this is very very short in the context of large corporations.
"That's because you should never have first 6 and last 4 in the same place at the same time, particularly to someone who is not the owner of the card!"
Sounded to me more like "of course they fixed it fast, this is a serious issue", and undermined the speed it get resolved. Probably my bad.
