I've seen a couple cases now where Spacey appeared to have run but didn't detect trailing spaces; I think all or most of these have been in infra/infra.git with tricium-dev.

Example:
https://chromium-review.googlesource.com/c/infra/infra/+/1142693/1/go/src/infra/tricium/api/v1/function.proto
https://chromium-swarm.appspot.com/task?id=3ec8a326792aac10

It's possible that this might not just affect spacey; but I think it's an analyzer issue, not a Tricium issue, since in that task it clearly ran on the file but didn't produce any comments.