Hey @tristan083,
thanks for the reply!
We actually use Event Calender Pro with Polylang Pro. We’ve now debugged a little more, here’s the result / current status:
In your plugin’s file src/views/v2/month/calendar-header, there is a function called tribe_events_get_days_of_week. This function returns an array of days and it works perfectly fine for the English version of the calendar. If we switch to the Spanish version, it works fine on initial page load for the month view – but if we switch to day view and then back to month view, the function suddenly returns the English names for the week days and therefore results in the warnings.
In short, the function tribe_events_get_days_of_week returns the non-translated versions after switching the views. Is there a way how we or you could fix this?