There Are Lower Leveled evolved pokemon than the level they evolve at. Not To Mention, Some Pokemon That Evolve by Stones ARE Sometimes found in the wild, like clafbles, and wigglytuffs in Mewtwos Cave, in Red/Blue. I Have Seen Lvl 8 Furrets in The Wild, Along With A Lvl 12 Golbat:)
So If You Are Asking If It Was A Glitch, The Answer is No, It Is Normal:)
Hope This Helps:)