I was totally thinking I did something terrible wrong when trying to copy files through a jump server. It turned out, to be nothing related to jump server but apparently a known issue with SCP silently failure when something funny going on with .bashrc It took a few searches to lead to these results and hopefully it will help you too.
The solution is suggested here: https://www.fir3net.com/UNIX/General/why-does-scp-file-transfer-fail-but-there-is-no-error.html
# If not running interactively, don't do anything
[[ $- == *i* ]] || return
Also detailed here in StackOverflow: https://unix.stackexchange.com/questions/18231/scp-fails-without-error