Refresh changes data color

I have a report that has data colors.
We are saving to Reporting Services not cloud.

When you run the report it shows different colours for each of the data values
example
if the field value is Dog then the color is blue
if Cat then Green
Bird then red

if you refresh the web browser it will change the color.

press refresh (with no data change)
the dog entry changes from blue to yellow, cat from green to black

refresh again and Dog changes from yellow back to blue

it is not consistent, sometime with a refresh the color doesn't change, it seems random
but it sticks to only two colors for Dog it sticks to blue and yellow

This seems like a bug, is there a work around?