server side imports of the form "./foo" used to work and now fail

Example:

import { taskCache } from './config';

This was working for many versions. I've created a new branch, added a bunch of new code which appears to have caused a new issue with this import style.

Now there are dozens of compile errors in the old code. ALL imports of this nature are failing. To make them compile again, I seem to have to do a pattern like:

import { taskCache } from "../server/config.js"

What could cause this behavior - and why do I need to make this change across a lot of imports which used to just work? I have not updated wasp.