Thanks, the -n option does work around this. I was very surprised to see input going to a backgrounded process but it seems that it is actually being stolen by the ssh control master process, which is not under bash's control.
- bash 4.4 messed up input with certain background processes Grisha Levit
- Re: bash 4.4 messed up input with certain background pro... Chet Ramey
- Re: bash 4.4 messed up input with certain background... Grisha Levit