Home, back and list buttons have stopped working, some settings item disappeared, some are empty

• /e/ version: 0.7-2020011737872
• Device model: peregrine (Motorola G 4G)
• When it started to occur: some days after upgrading to 0.7-2020011737872
• Reproducible with the last /e/ version: don't know
• Reproducible with LineageOS: don't know

Summary

Some days after I updated (through OTA) my phone to 0.7-2020011737872 some troubles appear suddenly :

• home, open apps list and (in a less deterministic way) the back buttons have stopped working ;
• some settings (namely at least the Buttons on) have disappeared ;
• some others settings have unexpected behavior (Developer options is said to be unavailable to the current user, Users is unaccessible) ;
• recovery was unavailable (adb reboot recovery did make the phone just boot)

The only way I was able to fix it was to :

1. boot in fastboot mode
2. flash recovery with TWRP image
3. boot in recovery (through fastboot, using physical boot when shutdown, aka Volume up + Power, did not work).
4. Wipe everything (every partitions)
5. Copy the /e/ image to the SDCARD
6. Flash it
7. Reboot

Now everything seems back to normal.

The only event worth noting is that before (one or two days before) stopping to work but after upgrading to 0.7-2020011737872 the battery discharged completely (I forgot to recharge it).

• The device is unusable
• The bug is the source of a data loss or a big waste of time
• The bug concerns a third-party application
• The bug concerns security
• The bug concerns privacy

The problem

Steps to reproduce

I don't know since it appears suddenly.

What is the current behavior?

see summary

What is the expected correct behavior?

see summary

Technical informations

too late I fixed by reinstalling, sorry.

Solutions

Reinstalled completely, see Summary.