Flutter Windows Host Engine has been failing since 2020-12-14 with false positives(the build is green even though it has failures). This can be affecting uploading windows web engine artifacts:

• This is the first try build failing with the error: https://ci.chromium.org/p/flutter/builders/try/Windows%20Host%20Engine/17186
• This is the first failing build prod build: https://ci.chromium.org/p/flutter/builders/prod/Windows%20Host%20Engine/7985