Five seconds on 12...h6 gave back most of a winning advantage, and the move right after it you found the best move on the board and never let go again.
The doubled c-pawns after 10.Bxc6 bxc6 bought you the b-file and a solid d5, and by move 12 the engine had you better by a pawn and a half. Then one quiet move nearly undid it.
12...h6 — the poke that invited the wrong trade
Five seconds, and the position went from -1.6 to -0.3. Poking the g5 bishop looks free, but it asks a question White answers well: Bxe7 Qxe7 Na4 Rab8 b3 Rfc8, and the pin resolves on his terms with your knight off the board.
f6 asks the same question and builds while it asks — f6 Bd2 e5 Ne2 e4 Qc3, still -1.5, with a pawn centre rolling and the f3 queen running short of squares. One move only annoys; the other annoys and gains.
Before a pawn move that touches one of his pieces, name the trade it invites and ask whether that trade is one you want.
13...Qb6 — two targets, and a bishop with no square
13.Bh4 kept the bishop on, and Qb6 was the engine's first choice against it: b2 and d4 attacked at once, and nothing good for the bishop to do. The line ran Bg3 Bxg3 Qxg3 Nf5 Qd3 Qxd4 and the position went to -2.2 — the whole advantage back, plus interest, in one move.
This is the scan working. You looked at what his piece could and couldn't do before you chose, which is exactly what didn't happen one move earlier.
15...Qxd4 — good enough, and there was better
After 15.Na4 the knight had walked away from its defenders. The engine's answer was Qa5 Bf6 Qxa4 b3 Qb5 c4 — you take the knight and ride out the pawn hits a piece up. You played 15...Qxd4 instead, which won the d4 pawn, took the queens off, and led to an ending you converted without a single flagged move. Nothing wrong with it; it just wasn't the most.
When he moves a piece to the edge of the board, count its defenders before you count anything else.
Phase notes
The conversion is the part of this game worth keeping. 18.Bg3 Nxg3 19.fxg3 handed you 19...Bxg3 — a second pawn and his kingside cover in the same move — and from move 15 to the end the engine flagged nothing you played. Rooks to the open files with 20...Rfc8 and 21...Rab8, then the break with 23...c5 and 24...c4. That is what technique looks like, and it used to be the missing part.
Profile check
Is the quiet-position scan still leaking? Yes, once. 12...h6 was five seconds in a position with nothing forcing in it, which is the same shape as the miss from the last pair: the scan fires when the board looks tactical and sleeps when it looks calm. What has changed is the other half of the file — converting a won position, which used to be the frontier, has now held twice running.
What to drill next
- Quiet-move puzzles — positions where the best move isn't a check or a capture. That is where both of your recent errors have come from.
- The position before 12...h6 — find f6 and play out f6 Bd2 e5 Ne2 e4 Qc3. Beat the engine from here three times running.
- Hanging-piece puzzles — the Qa5 shape: a piece that has stepped away from everything defending it.
When nothing is forcing, spend the ten seconds anyway and say his best reply out loud before you commit.