How to stop double message send in Flask based Slack application

I'm currently working on a custom bot for a Slack workspace to send messages when specific entries are given on a Google Sheet. I'm using a simple Flask setup with the Slack SDK and pydrive. I'm running into an issue where each message that is sent "asynchronusly" (i.e. not triggered by a specific Slack event) gets sent twice when running the Flask application. If I disable the Flask app, I only get one instance of the "Restarting Money Bot" sent. If the server is running, I get two instances, back to back. If the server is running and I respond to a slash command (test_command()), I only get the single response as required. I've attempted to alter the send method (using a raw API call rather than the SDK method) to no avail; I'm not sure where else to go with this issue.

Here's the code that's causing the issues. slack_handle just has simple wrapper functions for the API calls so I can keep Slack tokens and signatures local to one file:

from flask import Flask, request, redirect, make_response, render_template, send_from_directory

import os
import logging
import threading
import time
import json

from flask.wrappers import Response
import slack_handle
import drive_handle

logging.basicConfig(level=logging.DEBUG)
bot = Flask(__name__)

drive_access = drive_handle.gdrive()

@bot.route('/slack/test', methods=["POST"])
def test_command():
    if not slack_handle.verifier.is_valid_request(request.get_data(), request.headers):
        return make_response("Invalid request", 403)

    td_test = threading.Thread(target = test_command_thread)
    td_test.start()

    return Response(status=200)

def test_command_thread():
    slack_handle.sendMoneyBot("Money Bot is active :heavy_dollar_sign:")
    slack_handle.sendMoneyBot("Last refreshed " + str(drive_access.access_time) + " minute(s) ago")
    slack_handle.sendMoneyBot("Good connection: (" + str(drive_access.access_status) + ")")

# To run prior to server start
slack_handle.sendTreasurer("Restarting Money Bot")

td = threading.Thread(target = drive_access.mainDaemon)
td.daemon = True
td.start()

# Local server debug
if __name__ == "__main__":
    port = int(os.environ.get('PORT', 5000))
    bot.run(host='0.0.0.0', port=port, debug=True)

Any help would be awesome