Yes, according to the super spreader theory which has been proven. Also according to reports, many highly exposed first wavers ended up contracting covid during the 2nd wave.
Super spreader means that some are much more contagious than others, but I didn't see studies that showed that someone whose close presence other household members are in for hours every day may have never been contagious, and the fact that they never tested positive does not imply any element of temporary immunity.
First wave household members getting sick now is also not a proof. It seems likely that they had some sort of temporary immunity then, which they have since lost. This is not a foreign concept to us; that immunity from coronavirus colds lasts 4-6 months. It would be logical that many who had been immune then no longer are. These seem to be the main people driving the uptick these days.