Running multiple singularity exec commands in Bash script

[treigerm]

I am trying to create a Bash script which executes a command in a Singularity container multiple times. However, I get an odd behaviour insofar that the script terminates with an error after I have run the first singularity exec command.

Example script exhibiting the behaviour:

#!/usr/bin/env bash

singularity exec scam6_ppe.sif /home/scam/run_scam6_configuration.sh
echo $?
echo "first success"
singularity exec scam6_ppe.sif /home/scam/run_scam6_configuration.sh
echo $?
echo "second success"

The script succesfully executes the first singularity exec command and returns with exit code 0 but when it reaches the second singularity exec command it errors with: [23] + 3455 suspended (tty output) ./scripts/scam_evals.sh.

I have already tried setting stty -tostop as suggested here in my shell but that did not resolve my issue.

I am able to succesfully run multiple singularity exec commands outside a script using the command line. Sadly, I cannot provide a MWE for the run_scam6_configuration.sh script as it calls a complex simulator written in Fortran. However, the run_scam6_configuration.sh script itself does not start any background processes if that is of help.

Any ideas what might be causing the issue and how I should go about debugging it?

Singularity version: 3.0.1
OS: Ubuntu 16.04.7 LTS (GNU/Linux 4.15.0-220-generic x86_64)
Shell: zsh 5.1.1 (x86_64-ubuntu-linux-gnu

[dtrudg]

The Singularity and Ubuntu versions used here are very old, and not supported. I'd recommend trying to run the same script on a newer OS, using a current Singularity version (4.1.2). It's unlikely anyone will have an old install to try and reproduce this on.

[treigerm]

Thank you for the response. Unfortunately, this is happening on a shared resource for which I have no admin rights. I will try to get the admin to provide updates.