For as long as I've played DC, there has been a visual indicator that breeding is in process via little floating hearts and the two parent dragons circling around the breeding center. When breeding is complete, a large red heart appears above the breeding center.
When I loaded DC this morning, that had changed for me: All breeding centers had large hearts above them, even though only one was complete. The sanctuary had a yellow heart, and the other two had red hearts. One of the other two had a small "new" symbol attached to the upper left of the large red heart.
I will test when the sanctuary breed is actually complete to verify whether all breedings in the sanctuary get a yellow heart, or if it means that it is a sanctuary-specific breed. If the yellow indicates that the breed can only occur in the sanctuary, then that's awesome (though wouldn't green be more consistent with the dragon-source icon theme?), but if it literally only indicates that the breeding is happening in the sanctuary, it seems confusing and worthless.
Similarly, if all of this comes at the cost of no longer having a big visual indicator that a breeding is complete, I'm very much against the change!