Sometimes, if the orchid has certain ancestry, you can get leaves with patterns, certain hybrids better than others. The species Phalaenopsis Schilleriana and Phalaenopsis Stuartiana, for instance, both have markings on their leaves. Their offspring may or may not have some degree of coloration in their leaves.
A deficiency of phosphorous and cooler temperatures. or higher light with red/pink coloring in the flower can also cause reddish coloring in the leaves.
If the roots and leaves are healthy, the orchid is probably fine.