Running collections back to back causes errors

When I run two collections back to back the first one works fine but the second one fails. It fails because it is trying to use the url from the previous collection. I can run them seperatly and they run just fine as long as I wait long enough. This happens using newman and postmans collection runner. Any advice on what to do?

Thanks

How is the URL being supplied to the tests? Is it dynamically set as an environment variable during test?

Iā€™m passing the variable location in the command using -g. It has to be some kind of caching as we were able to get it to work by running one in dos command window and the other in powershell as a dos command.