Hey Michael,
Welcome back to the forums 🙂
Weird, indeed! Would you mind updating to The Events Calendar version 4.0.5 (released today) and let me know if the problem still occurs? I just tried replicating the issue on versions 4.0.3, 4.0.4, and 4.0.5 but was unable to reproduce the errors described. More information on the latest version can be found here.
Next, I would recommend running through our Testing for conflicts article. Keep me posted with any new information and have a great weekend!