ILS many weaknesses
Read the AIM Section 1-1-9 para k. This issue has been well known since at least 1939,if not before. It is why we have critical and sensitive areas in ICAO Annex 10. It is also one of the many reasons why GLS (and RNP) will soon replace ILS, not the least, that ILS is far too expensive to install and maintain, and knocks itself out even in simple snowstorms.