Script ./src/make_custom_pi_os returns unexpected error

I start works with repo and just flow the tuturial from ReadMe file. Clone the repo and try to execute
./src/make_custom_pi_os -g test the script returns the following error:

Settings:
making dstro in test
variant: raspios_lite_armhf
./src/make_custom_pi_os: line 36: MULTIPLE[@]: unbound variable

I have no idea, about how to fix the problem. Sure i can just remove the part of script which produce the problem, but the way doesn't look right for me.

for a in "${MULTIPLE[@]}"; do
    echo "  $a"
done

My envirment
MacOs sonoma: Version 14.0
Processor: 2,4 GHz 8-Core Intel Core i9