I'm a pollen chunker who know things about breeding ( I am doing some personal crosses ) .
So each time you are growing the same strain you get 2 phenotyoes , it can happens when the palnt has not been stabilised enough , for example my pineaple express were all the same , my critical kush from barney's looks like every seeds is growing the same phenotype , but when I grew some amnesia I had many shapes , smells , and style o buds depending on each plants. So you can end up with similar plants if the strain is stable or differents style of plants if the strain is not.
New growers and old growers can tell the same thing , sisters have genes in common but are not sharing the same genetic code or they would be twins , as long as they are not twins they are not similar , and are actually NOT THE EXACT SAME GENETIC , it's the exact same cross but not the exact same genes or you would not have any PHENOTYPES you would only have a TYPE which would have been the same for every plants from a same strain but it's not like that.
The only way to have a stable genetic is to bring it to the F7 but at that generation ( the 7th generations ) you ca have plants that are 99% the same due to multiples crosses to keep a specific trait . Nowadays most of the strains are F1 or F3 , some are S1 which means self polinated and even with a self pollinated plant you are not sure to have a copy from your original plant but something close to.
That said it's normal to see differents shape , siwe and smell on 2 plants from a same strain , the best exemple is the Cheese which is just a skunk phenotype ( is a cheese sharing the same exact genetics as the skunk ? NO )
With autos the plants are sharing the same ancestors ( a photo and an auto ) , but mostly after 3 generation which is enough to get something stable but not enough to get something super similar from a plant to another like a inbreed line ( more than F7 ) or a F7 stabilised strain.
So to say it the simple way , you'll always have differents phenotypes even with stabilised strains , that said many companies are talling you how many phenotypes you can expect to find and which one is the one to hunt for