Ay, anak I dulu juga pernah macam tu around that age! Honestly most of the time it's just a phase, anak-anak suka experiment dengan cara jalan yang baru, especially kalau diorang tengok orang lain buat. A few of my mum friends' kids did the same thing, and it went away on its own within a few weeks or months la. But if it's persisting beyond a few months or ada kaki dia sakit, better check with the pediatrician just to be safe, sebab sometimes bisa ada habit atau tengion issue yang perlu ditonton.