This is true not only from the stand point of another strain pollinating her, but also could be her sister plant that herm'd and pollinated her, which is different from an S1. The point of an S1 is to go on the hunt. For example, you pop 100 seeds. Of that 30 maybe even 40 probably won't be what your looking for. Maybe too much stretch, issues with pm or mold or whatever. The rest of that 60-70 with have more slight variations you can hunt thru to decide what you like in structure or production or whatever you might want to flower out. And then you'll find the true keepers, maybe only 5-6 that are the true gems. Those will be even better than the original mother that you self'd. These are the ones you want to mother out keep forever. An S1 unlocks the full spectrum of the plants DNA code, from extremely bad to extremely amazing.