Hi, co-founder of Roam, Josh here. I don't recall your case ever being brought up to me, but as Baibhav said in his comment, we have strict no-access rule for engineers. They (and me) are only allowed to open your graph if given explicit permission by you through support. We have always had this rule and it's in our terms and conditions.
I think I found your account and I don't see any access logs to your graph from anyone other than your account. If you can provide any more info or screenshots of we would be able to dig deeper into exactly what you saw. It could have been a console log or a hard coded employee email in the code.
We've always cared deeply about user's privacy and ownership over their notes. This is why we've had this policy from the start and focused heavily on local first features and data portability. We offer fully offline graphs, where the data never touches our server and is never able to be accessed by anyone on our team. We also offer fully encrypted graphs, which are stored on our servers but are not able to be read by anyone without the password (our team cannot read your data).