In a recent competition I encountered a bug where perfectly valid code failed to compile after submission, returning a blank compilation error, despite compiling on my machine. Experimentation with making minor modifications, including simply adding a comment revealed that every submission of this source file failed to compile, while even adding a comment caused it to be accepted.

Relevant submission IDs are: 13270104 13270364 13292673 13292686 13292732

Compiling with the exact same compiler version on my machine works fine.