Map.update inside for loop

Hi, I’ve just started learning Elixir.
For one of the applications I’m developing, I have the following code:

use Bitwise
sensor_data = %{sensor1: 0}
for n <- 0..9, do: sensor_data = Map.update!(sensor_data, :sensor1, &(&1 ||| (1 <<< n)))

This produces following output:

[
  %{sensor1: 1},
  %{sensor1: 2},
  %{sensor1: 4},
  %{sensor1: 8},
  %{sensor1: 16},
  %{sensor1: 32},
  %{sensor1: 64},
  %{sensor1: 128},
  %{sensor1: 256},
  %{sensor1: 512}
]

But the expected output should be:

[
  %{sensor1: 1},
  %{sensor1: 3},
  %{sensor1: 7},
  %{sensor1: 15},
  %{sensor1: 31},
  %{sensor1: 63},
  %{sensor1: 127},
  %{sensor1: 255},
  %{sensor1: 511},
  %{sensor1: 1023}
]

If I run the following statement in iex session the sensor_data map gets updated like this:

sensor_data = Map.update!(sensor_data, :sensor1, &(&1 ||| (1 <<< 0)))
%{sensor1: 1}
sensor_data = Map.update!(sensor_data, :sensor1, &(&1 ||| (1 <<< 1)))
%{sensor1: 3}
sensor_data = Map.update!(sensor_data, :sensor1, &(&1 ||| (1 <<< 2)))
%{sensor1: 5}

Can you help me understand why does the Map.update!/3 doesn’t work inside a for loop?
I also tried with Map.update/4 Map.replace!/3 but no luck.