raspberry pi – Running hci lescan with timeout breaks the command

So the command sudo hcitool lescan outputs bluetooth addresses until ctrl+c is pressed. I want to have the command run for 20 seconds and capture the output. I tried running timeout 10 sudo hcitool lescan, but that gives me the following error: Set scan parameters failed: Input/output error

However, if I put sudo hcitool lescan in a .sh file and then run timeout 10 sh_file_name, it finishes executing without an error.

I tried making a .sh file with the following:

#!/bin/bash

output=$(timeout 10 ./test.sh 2>&1)
echo "$output"

However, now that gives me the original error.

What is the problem, and how do I fix it?