Those cron times may be inconsistent with your PC as they’re based on the time on the host server.
The thing is, my cron event is now gone so can’t be affecting any runs (not that it should anyway – it runs once a day, so if it fails, it will only affect that run. The hourly runs won’t be affected by my event).
So, we’re back to why you’ve had issues and I can’t tell. It may be a more general issue with your cron – WordPress is notoriously fickle when it comes to WP Cron, as it’s reliant on visitors to your site to ensure that things are kicked off (which is why so many people report issues with scheduled posts not publishing at the right time).
Why it should have gone wrong after installing my plugin, I don’t know. My cron doesn’t appear to be the cause. If it’s the housekeeping of transients that’s the cause, then you have a deeper issue – transients are intended to be temporary data storage. If removal of any of those has affected your cron runs then it may be because something else is (incorrectly) reliant on the data. I would suggest standard diagnostics now – disable all your plugins to see if this rectifies your cron issues (if not, it’s your core installation or hosting). Then enable each plugin at a time and re-test.