I just got this Tamron AF 70-300mm 4-5,6 Di LD Macro 1:2 for my Canon 500D.

I tested it yesterday and it works fine. Only one problem: I took pictures of a flower which is dark violet. But when I look at the pictures on screen, the color is kind of light blue, which is a big difference. I use a UV filter and the sun block hood, and there was no sun light at that moment. I changed to my Canon 55-250mm, and it didn't have the same problem.

I don't know if this is a technique problem, or an issue with this lens. Does anyone have the same experience?

This is the one I took with Tamron, I resized it:

And this one I took with my Galaxy S7: