Istredd doesn't need a close and active telempath bond to know when something is wrong with Yennefer. They can connect any time they want, but he's learned over time just by reading her body language when she is struggling. The benefit of knowing someone through the most formative years of their life. He knows better than to ask her in public in Thorne, when her defenses are the highest, and these days he's less and less comfortable in Thorne, even in warded areas.

If they're going to actually talk, they need somewhere there is no chance of being disturbed. So he leaves her a message in the private 'network' simply saying Meet me in our spot when you have a chance, please.

Yennefer is now aware that permanently underneath his Horizon library is a replica of the place they would meet as youths to talk and be together. It was their only refuge as they struggled through their training, and he created it for when he needed peace or to think. All these decades later and it is still the place that calms him down, clears his thoughts.

The door down to it is only visible and accessible to Yennefer so when she arrives she'll see it ready for her. What he did add, since this is the Horizon, is a slightly more comfortable seating area with blankets by the rock she often leaned at. The easier to sit and talk, although it is still on the ground like it used to be. No fancy chairs or tables. Something simple, private.

He is leaning against the rock when she comes in, writing in one of his many journals. There is an entire section of this library at this point with his notes on everything he's seen. It never really ends. Istredd glances up when he senses her arrival and it disappears from his hand, off to a shelf somewhere.

His eyebrows go up at her. "Yenna. What is bothering you?" He never beats around the bush with her, she likes people to get to the point. So does he, really.