diff --git a/internal/task/tagx.go b/internal/task/tagx.go
index 87c91631..d6e63a5a 100644
--- a/internal/task/tagx.go
+++ b/internal/task/tagx.go
@@ -471,6 +471,18 @@ func (x *TagXReposTasks) findGreen(ctx *wf.TaskContext, repo TagRepo, commit str
 		}
 	}
 
+	foundCommit := false
+	for _, rev := range repoStatus.Revisions {
+		if rev.Revision == commit {
+			foundCommit = true
+			break
+		}
+	}
+	if !foundCommit {
+		ctx.Printf("commit %v not found on first page of results; too old or too new?", commit)
+		return "", false, nil
+	}
+
 	// x/ repo statuses are:
 	// <x commit> <go commit>
 	//            <go commit>
diff --git a/internal/task/tagx_test.go b/internal/task/tagx_test.go
index f1a287ef..0ac3916c 100644
--- a/internal/task/tagx_test.go
+++ b/internal/task/tagx_test.go
@@ -199,6 +199,26 @@ func TestIsGreen(t *testing.T) {
 			},
 			wantGreenRev: "tools-1",
 		},
+		{
+			name: "not green yet",
+			rev:  "tools-1",
+			lines: []revLine{
+				{"master", 3, 1, true},
+				{"release-branch.go1.19", 1, 1, false},
+				{"release-branch.go1.18", 1, 1, true},
+			},
+			wantGreenRev: "",
+		},
+		{
+			name: "commit not registered on dashboard",
+			rev:  "tools-2",
+			lines: []revLine{
+				{"master", 1, 1, true},
+				{"release-branch.go1.19", 1, 1, true},
+				{"release-branch.go1.18", 1, 1, true},
+			},
+			wantGreenRev: "",
+		},
 	}
 	for _, tt := range tests {