Flask doesn't seem to recognize file changes
I was having a similar issue and deleting the .pyc files solved it for me.
A little background:
I've been working on this project for about six months now and it's been running on Flask the whole time. Everything has been fine, multiple versions of the backend have been deployed live to support an app that's been in production for months now.
The development cycle involves writing everything locally and using Flask-Script's runserver command to test everything locally on localhost:8080 before deploying to a dev server and then finally to the live server.
The Problem: The other day my local flask instance, which runs on localhost:8080 apparently stopped respecting my local files.
I tried adding a new view (with a new template) and I got a 404 error when trying to view it in my browser. 
I then tried making some test changes to one of the existing pages by adding a few extra words to the title. I restarted flask and none of those changes appeared.
I then went as far as deleting the entire views.py file. After restarting flask again, much to my dismay, I could still view the pages that were there originally (i.e. before this behavior started). 
Finally, I made some changes to the manage.py file, which is where I put all of the Flask-Script commands, and they weren't recognized either. It's as if flask started reading from a cached version of the filesystem that won't update (which very well might be the case but I have no idea why it started doing this or how to fix the issue).
FYI: Browser caching shouldn't be an issue b/c I have the dev tools open with caching disabled. Plus the fact that changes to manage.py aren't being noticed shouldn't have anything to do with the browser.