Looking at the moment-timezone on github, looks like you are totally right.
I think this will require some further testing on our end to check why we wasn’t able to reproduce with the current setup we use, if moment is really still required as a full dependency (But your tests seems to show it isn’t), and since I’m now able to reproduce, no issue for me to take this from now on.
Let me know what suits you the most 
Great news! I mean, I might open a PR simply to have it point to it in my project’s package.json. I might even simply have it point to my fork so as not to clutter the PR section. In any case, I’ll keep an eye on Forest’s repo for when the fix is live and simply switch it back. We are going into production this week, so it’s something my team needs asap.
This was more to avoid “stealing” code here since you made most of the work 
Anyway, I opened a PR available here, containing the fix you mentionned : https://github.com/ForestAdmin/forest-express-mongoose/pull/428.
I’ll push it to review once my tests are finished, but you should be able to reference it in your project and tell me if that works for you.
Again, thanks you for your help here
Oh! Nevermind! It was nothing and it’s always great to help. I really like Forest Admin so I don’t mind helping a bit to make it better.
Thanks @jeffladiray
The fix was just released, updating to forest-express-mongoose@6.3.9 seems to fix the issue on my end.
Let me know if the fix works fine on yours
Indeed, the issue is fixed. Thanks both of you !