I think it is a bug inside the component when you use the calendar inside a list view. I have made an example which demonstrates the bug (see json below, i can not upload it as a separate file since i am a new user). In the example I call a rest api for the data. When you run it twice you can see the error in de debug console.
JSON:
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And thanks for joining us in office hours today; it's always nice to see a new face.