Error in case syntax, but syntax is there: Syntax error: word unexpected (expecting "in")

Question

I have a bash script that accepts input from the CLI using flag variables. Here's the script:

#!/bin/bash

d_flag=''
b_flag=''
c_flag=''
verbose='false'

print_usage() {
  printf "invalid flag"
}


while getopts 'd:b:c:v' flag; do
    case "${flag}" in
        d) d_flag=${OPTARG} ;;
        b) b_flag=${OPTARG} ;;
        c) c_flag=${OPTARG} ;;
        v) verbose='true' ;;
        *) print_usage
            exit 1 ;;
    esac
done

echo $d_flag
echo $b_flag
echo $c_flag

exit 0

Here is the returned error:

user1@debian:/opt/scripts/# sh inputs.sh -d directory -b backupdir -c configdir -v
: not found2: inputs.sh:
: not found7: inputs.sh:
: not found10: inputs.sh: }
: not found11: inputs.sh:
: not found12: inputs.sh:
inputs.sh: 14: inputs.sh: Syntax error: word unexpected (expecting "in")

I cannot figure this out, as I have "in" in the syntax of the case statement. Can anyone help me figure this out?