A bit new to this arnt you, depending on how the roots are growing, for example, if they start getting root bound to the pot, cutting back roots is necessary to promote them to grow into there new medium, it dose take them a little while to recover, but thats only because the plant spends more energy growing new roots to support future growth, dont forget that cuttings start with no roots at all, just a bit cut off the plant, so no it should be fine, these are weeds after all, you can butcher them back to almost nothing and still regrow them.