dateInput does not show as Calendar input choice, but a text input box

General
1

what are the specific reasons why my dateInput shows as a text input box, rather than a calendar input choice? I am very puzzled over this, because recently I can see calendar input, now it always shows a text input instead.

dateInput('dateSelect',label = NULL,value = Sys.Date()-1)

2

the same applies to my dateRangeInput. I am totally puzzled and has been looking at it for days. Hope someone is able to provide some hints, thanks.

dateRangeInput('temp_DateRange',
                            label = h4('Date range'),
                            start = "2020-01-01",
                            end = Sys.Date()-1,
                            separator = " - ", 
                            format = "yyyy-mm-dd"))
4

I have to switch to airDatepickerInput now, which works perfectly for me.