I’m really surprised by this behaviour of set -e (errexit) flag.
I thought it will stop at any “unhandled” line that returns non-zero value

See my simple script and output

#!/usr/bin/bash

set -o errexit   #set -e
set -o nounset   #set -u
set -o noglob    #set -f  
set -o pipefail

echo "START"

fun()
{
    echo "Starting fun that has wrong command after wrong command"
    
    touch /not-existing-directory/not-existing-file.txt
    echo "ERROR: ${?}"
    
    echo "TEST LINE" >>/not-existing-directory/not-existing-file.txt
    echo "YET ANOTHER ERROR:${?}"
    
    cat /not-existing-directory/not-existing-file.txt
    echo "STILL EXECUTING DESPITE SO MANY ERRORS: ${?}"
    
    echo "WHY THIS AND FOLLOWING LINES ARE PRINTED? WHY ARE WE STILL EXECUTING DESPITE set -e AND SO MANY UNHANDLED NON-ZERO ERROR CODES?"

    return 0
}

if fun 
then
    echo "OK: ${?}"
else
    echo "ERROR: ${?}"
fi

echo "END"

Below is output:

START
Starting fun that has wrong command after wrong command
touch: cannot touch '/not-existing-directory/not-existing-file.txt': No such file or directory
ERROR: 1
./test.sh: line 21: /not-existing-directory/not-existing-file.txt: No such file or directory
YET ANOTHER ERROR:1
cat: /not-existing-directory/not-existing-file.txt: No such file or directory
STILL EXECUTING DESPITE SO MANY ERRORS: 1
WHY THIS AND FOLLOWING LINES ARE PRINTED? WHY ARE WE STILL EXECUTING DESPITE set -e AND SO MANY UNHANDLED NON-ZERO ERROR CODES?
OK: 0
END

My versions: Bash 5.1.16 on Ubuntu 22.04

Could you explain this behaviuor to me? I presume it’s not bug

Best regards!