I created sample table.
First I created chart typrectangular. As You can see, it takes the data values
as the same group of data. (picture 1)
Then I changed the char type to cake. What happens? Now it distinguishes the
data and gives them different colours and different legend titles (pic 2).
I change to other type of rectangular chart -colors are gone and legend shows
just one type of data (pic 3).

Let's see, how it applyes to created chart. I set the chart to display values,
and to display them as percentage. For cake, it shows different data with
different colours and the correct percentage (pic 4).

But I change the chart type to cake -and colours are gone again, and the
percentage shows for all data the same value: 100%! (pic5) I deleted the legend,
but logically, it was the same (one colour one row).

I needed to represent some data in rectangular chart and instead of correct
values and different colours, it shows one colour, 100%. But while I wanted to
make more snapshots, I opened the file again and wow! The rectangular chart now
represent colour too! Why it didn't before? (pic 6)

For the last subtype of rectangular chart, it even shows all 100% values
graphically too -with identical length too! But since this was after opening the
file (before taking snap 6), it's still with mixed colours! (pic 7)