Did you reinstall the M73ETAOveride plugin from the following url? If it's still not working as expected, maybe post an issue to the issue tracker of the plugin repository here.
https://github.com/jneilliii/OctoPrint-M73ETAOverride/archive/master.zip
I just pushed an update to my fork that should prompt to restart after install.
I do not have either of those plugins installed.
I did restart Octoprint, more than once. Looking at the results I'm seeing on a current print job, I do not think it's actually working with the remaining time. It's now 16:15, Octoprint shows print time left - 40 Minutes, ETA 16:45.
So the ETA says it will be done in 30 minutes. The display on the printer agrees. I suppose this could still be a rounding/truncating issue but it seems a little unlikely.
It does seem that there may be some conflict but I can't figure out what it might be. Here are the lines from the log for all the loaded plugins. Maybe you have an idea which one?
| Action Command Prompt Support (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/action_command_prompt
| Announcement Plugin (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/announcements
| Core Wizard (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/corewizard
| CuraEngine (<= 15.04) (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/cura
| Discovery (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/discovery
| DisplayZ (0.1.0) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_displayz
| FileManager (0.1.3) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_filemanager
| Firmware Updater (1.0.0) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_firmwareupdater
| Fullscreen Plugin (0.0.4) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_fullscreen
| Logging (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/logging
| M73 ETA Override (1.0.0) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_m73etaoverride
| OctoPi Support Plugin (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/octopi_support
| Plugin Manager (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/pluginmanager
| Printer Safety Check (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/printer_safety_check
| SMS Notifier (with Twilio) (0.3.1) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_smsnotifier
| Software Update (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/softwareupdate
| Virtual Printer (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/virtual_printer
Yes, I installed from the URL in this thread. Installing the other version resulted in the errors when the plugin loaded shown above.