Setting DateField's RangeEnd Leads to calling changeVariables()


I am experiencing some unexpected issue with the DateField object. Upon initializing my DateField start time and end time, whenever it is clicked, I call the setRange End to a certain value but this leads to calling the changeVariables() which sets my Date value to the current year. The resolution I used for my DateField is Year. Please enlighten me why this happens and how to prevent it.

Thank you in advance!

Best regards,