Just made an observation: Because I had to take a bunch of screenshots and wanted to use my big screens, I reset the scaling to 1.0 and rebooted. As expected, spectacle worked. Then I set the scaling back to 1.25 and re-logged. And spectacle still works! It even survived a reboot! I would encourage everyone to try that workaround and hope it aids in resolving this issue.
Just made an observation: Because I had to take a bunch of screenshots and wanted to use my big screens, I reset the scaling to 1.0 and rebooted. As expected, spectacle worked. Then I set the scaling back to 1.25 and re-logged. And spectacle still works! It even survived a reboot! I would encourage everyone to try that workaround and hope it aids in resolving this issue.