title: bazel recompiles protobuf more than necessary
body: <p>I followed <a href="https://blog.bazel.build/2017/02/27/protocol-buffers.html" rel="nofollow noreferrer">this example</a>, and it works fine.</p>
  
  <p>But sometimes (not always) when I changed some application level code that's totally not related to protobuf and rebuild, bazel spends all its time recompiling protobuf.</p>
  
  <p>Any suggestions what I can try to debug this?</p>