People don't talk about "backfilling trenches", they talk about "backfilling pipes" which is precisely the problem. They also will say things like "when you bac

People don't talk about "backfilling trenches", they talk about "backfilling pipes" which is precisely the problem. They also will say things like "when you backfill a pipe, use sand or granite." It pretty obvious why an LLM would be confused by this.