Icon of time machine on the desktop

Hello,

I have updated to El Capitan in two iMacs. All went very well. One thing has been changed, and I wonder if it is with others as well.

In 10.10 the icon of the Time Machine disk on my desktop was as followed:

But now, in the two Macs, the icon of the Time Machine external disk on the desktop in both Macs remain yellow as it is and as follow:

In the Time machine software the two icons there are as it was always:

My question:

Is this is the normal case or something went wrong in my upgrade process.

What and where should I configure?

Thanks for your assistance