How to parse input string in Bash for an SSH command?

Question

When I run the ssh command with a variable declared in bash, it works ok. i.e. a="01-30-22-23-54"

When I pass in the string (representing the date) on the command line, I get the error message: bash: "01-30-22-23-54": command not found

How do I get SSH to consider this variable a string?

I've tried passing into the ssh command: $a, "$a", "{$a}"... im lost

Command Line Input: file.sh -a "01-30-22-23-54"

Parsing input:

while getopts ":a:" arg; do
  case $arg in
    a) a="$OPTARG";;
  esac
done

SSH Command:

ssh -o StrictHostKeyChecking=no -o IdentitiesOnly=yes -i ... '/bin/bash -s $a' << 'EOF' "$a"