Thanks for the update. Glad to hear the error is gone. A few thoughts, Soft Reset doesn't rollback the platform. Based on above details, your hub didn't update to 139, the first time, that's why it was available after Soft Reset.
and select Soft Reset. When it eventually comes back, down at the bottom there will be a link to restore a backup, click it and then select the backup that you created and downloaded.
It will load that and then will reboot. When it comes back up from that, hopefully the 500 will be gone.
Hint: you will need you Hub MAC address as the password to log in to Diag Tools to do the Soft Reset. The easiest way to do this is, before you go to Diag Tools (http://your.hub.ip:8081), go to Settings, Hub Details, and copy the MAC address, then paste it in to the password field when you log in to Diag Tools.
Oh, and welcome to the Hubitat community, @jasonpillet !