Certified GKH Gardening Expert
It looks like you have two different ages of blooms. As the yellow blooms age they turn the pink color. Rather than new blooms being pink and yellow. A rosebush named Rio Samba does this exact thing. The blooms are mostly yellow with a kiss of pink and as they age they turn totally deep pink. The only other reason would be that there are actually two different roses planted in the pots rather than one.