edit: adding in some sources
2014: "between 2030 and 2040" according to https://www.aivd.nl/publicaties/publicaties/2014/11/20/infor... (404) via https://tweakers.net/reviews/5885/de-dreiging-van-quantumcom... (Dutch)
2021: "small chance it arrives by 2030" https://www.aivd.nl/documenten/publicaties/2021/09/23/bereid... (Dutch)
2025: "protect against ‘store now, decrypt later’ attacks by 2030", joint paper from 18 countries https://www.aivd.nl/binaries/aivd_nl/documenten/brochures/20... (English)