I’m not sure what you mean by “bumping the version in source after a release”. If it’s after a release then you released it with the old version? Or do you mean prep the repo for the next version by incrementing it optimistically, in which case it probably depends on your branding model. But I don’t understand the “immediately” part of your question.

Where I work we don’t increment until we know what branch/version we are working on, and determine the semantic version, and then we still use tagging because we tag the version + build id which is computed at build time