Followed the steps at the bottom of the safe 3 wiping page.
Just finished: You will then see the option to perform a ‘Factory Reset’; press both buttons to begin the process.
Expected: Press the button on the right to select ‘RESET’, which will erase your device and restore it to factory settings
What happened:Modal displayed in top right stating: Error: ui-device_firmware_old
Other info:
Safe 3 displays waiting for host.
When you get to the bootloader, you should see “install fw” on the left button and “menu” on the right. Click “menu” to enter the menu in which you can use the buttons arrows to locate the “Factory reset” option.
If you press the left “install fw” button, you will go to the “waiting for host” screen, which then triggers a completely separate and unrelated Suite bug 
with the “firmware old” message.
We have seen rare cases when the “install fw” button is triggered unintentionally, possibly due to button jitter.
You can avoid the problem by, when plugging in the Trezor, you only hold down the left button instead of both. The KB page is wrongly saying that both buttons are necessary.
That worked. Thank you.