Here is the weakness. White first provides against Black’s P-Q4, and then starts a sharp attack on the King’s side.
15. B-Kt5 QR-Q1
P-Q4 at once is not feasible, because of BxKt.
16. PxP PxP 17. Q-B1
This brings the Q away from her file, which Black could now secure by P-Q4, followed by PxP.
17. … KR-K1
The proper continuation is the one outlined in the note above.
18. P-R3
White has now ample leisure to prepare the advance of his KBP.
18. … R-R1 19. RxR RxR 20. Kt-R2 B-QB1 21. P-KB4 Kt-K1 22. P-B5 BxB 23. QxB Q-K2