Restoring session puts all tabs in a single group

[Warix3]

When my PC loses power and if firefox was working then after I turn on PC again and turn on firefox there is a screen saying firefox was shut down improperly and if I use the option to restore the session then all of the tabs will be restored but put in a single last used group.
Firefox version: 67.0.2 (64-bit)
OS version: Windows 10 Pro 1809

[stefan-vogel-stalder]

Same problem under Linux/openSuSE Leap 15.1 FF: 60.8.0esr (64-bit)
After updating to FF 68.1 the problem went away

[KunjanChauhan]

Yes, I have this issue as well. There are times when FF crashes and upon restart all tab groupings are lost with tabs being reassigned to the pre-crash active tab. Is it possible to either build in a session backup function which stores a table of tabs and their groupings and the date time of the snapshot with an ability to restore or to integrate e.g. the "Tab Session Manager" or similar plugin? ty.