Hey folks, really sorry that you are facing this one. I've tried to replicate this, but seems to be an edge case and I haven't been able to reproduce it so far.
Could you please let me know what tab mode you are in? (Is it standard or compact?) and if you are able to observe, it what is the exact point at which the tab bar items disappear?
i.e. Are the front / back buttons visible, and then after creating a new window, they disappear? Do you quit the app in between, or is it strictly new windows? etc. Any reliable reproduction steps will be super helpful.
Thanks again for being patient and for reporting this.