I have found the answer. Using RedHad Enterprise Server 7 linux distribution and for R2020b compiled code, a specific patch is required.
The launch shell script generated by the MCC includes the change, but as I was using a custom launch script, the patch was not picked up. The error was catsed by the missing patch. Adding the line from the MCC-generated script solves the issue.
The line is:
# Preload glibc_shim in case of RHEL7 variants
test -e /usr/bin/ldd && ldd --version | grep -q "(GNU libc) 2\.17" \
&& export LD_PRELOAD="${MCRROOT}/bin/glnxa64/glibc-2.17_shim.so"
If you use the automatically generated launch script, then the change for R2020b is automatically handled for you.