I've had to stop using FF as my development browser because it chokes on large source maps. I used to find lots of issues in our web app that were only ever tested on chromium browsers. I don't anymore because the devtools are unusable past a certain point.
Can you please file a bug on Mozilla's bug tracker? They are usually quite responsive on well-documented dev related bugs - especially ones around edge-cases related to fundamentals like resource allocation.
You'd be doing a good thing that would help others.
