As an UXR, how do you manage being splained by a designer ?

As we all now it's common for a UX designer (or Product designer or UX/UI or whatever the trend is in your area) to be 'splained user needs, discovery, design by their product team. Or ignored. Or having their deadlines dismissed. What I see too often (but maybe it's because I'm a woman ?) is designers doing this to researchers. Being explained heuristics, being handed over assignments last minute, dismissing our remarks because they, too, do research so they know. How common is it and most importantly, how do you handle it ? Designers : why ? Do you catch yourself doing this ? Where does it come from (because I'm sure there is a legit reason why some of you do this... maybe very similar to why PrD crowd do it to you...) ?