Postgresql range_agg() Return empty list

I am using range_agg() function, it works fine with original table value

Query Result

But when I try to do some update for range value, it will give back an empty list

Select range_agg(b.r)
From (  Select int8range(lower(bin_range)+1, upper(bin_range)+5) as r   From bin_data) as b;

Query Result

I test with the same query in fiddle but no issue there

https://dbfiddle.uk/1MRn8hn6

All these query are running on pgAdmin4, wondering why it happens

Thanks
Han