Joan notices. She notices how quickly he skips past that particular program. Notices how the muscles of the shoulder her head is on tighten. That with the reaction Ted had to Keeley's story makes Joan wonder if Ted is homophobic. Considering where he's from and the macho sports he's coached, it wouldn't be all that surprising, if a little disappointing. She wonders if maybe that's what transpired between Ted and Sherlock. Maybe Shaun is gay and Sherlock noticed Ted's discomfort and called him out on it? It fits the evidence. Ted would be upset and Sherlock would want to let Ted talk to Joan about it instead of talk with her behind his back.

"Do you want to talk about it?" she says softly, since he's clearly at least somewhat distressed.