The earthworms shouldn’t be crawling into the collecting container on their own, just as they shouldn’t be outside the wormery. If they do, it means they don’t like something inside the container. It could be excess food, so take some away. It could be the lack of air. Check that the moisture level in your wormery isn’t too high.
If you're looking to get started with Worm Composting, please Wiggle on over to https://www.wigglywigglers.co.uk/wormeries.html and take a look at our Urbalive Worm Composters.