Factory reset + Format data fails to reset device (hero2lte)

[zzz2002]

• [x ] I am running an official build of TWRP, downloaded from https://twrp.me/Devices/
• [x ] I am running the latest version of TWRP
• [x ] I have read the FAQ (https://twrp.me/FAQ/)
• [x ] I have searched for my issue and it does not already exist

Device codename: hero2lte
TWRP version: 3.4.0.0

WHAT STEPS WILL REPRODUCE THE PROBLEM?

factory reset.
Format data
attempt to Reboot

WHAT IS THE EXPECTED RESULT?

error/warning about rebooting into a system without a system installed

WHAT HAPPENS INSTEAD?

system reboots normally into (in my case) into Lineageos 17.1 Beta.
It appears that the system reset and the format data failed (did nothing).

ADDITIONAL INFORMATION

I tried to reset/format data 3 - 4 times without success.
I eventually got it to work doing a factory reset and formatting data 3 times in succession without reboot in between. this appears to work as I go the error/warning.

I then flashed the version of lineage I wanted successfully.could not find logs

[bigbiff]

Hello. Please upload recovery.log of these actions for debugging.

[zzz2002]

Unfortunately I don't think I have the log from that episode. I have reinstalled LineageOS hero2lte beta twice since I had the problem. It took me a while to find out where to reports TWRP problems.
I am thinking of starting from scratch - stock install, install twp ....
If I run into the same problem then I will upload the TWRP log file.
Sorry I cannot be more helpful(useful)