Hmm, did you make sure that spheres were not grouped together? If I do this (select all spheres and then use the "replace by command") with a set of replicated spheres that are NOT grouped together, I get each individual sphere replaced by a point light. If they are grouped, I get one light as I would expect because in agroup they count as one object. This is in Vue 9 and 8.5 Infinite.

Ciao
TD