Uncaught (in promise) error

my Discourse instance is up to date with tests-passed. I had a report from a seperate user of my instance yesterday that a future week view wasn’t loading all the events. Having already noticed that this error ceased to affect UI of the Current week view, i tried to pinpoint the error on my Laptop. Below is the video re-production;

the same “lack of events” in a future week, can be re-produced the same on my Smartphone