diff --git a/src/DiagnosticsManager.ts b/src/DiagnosticsManager.ts
index 9d01f1e0b..2c69a852e 100644
--- a/src/DiagnosticsManager.ts
+++ b/src/DiagnosticsManager.ts
@@ -14,6 +14,7 @@
 
 import * as vscode from "vscode";
 import * as fs from "fs";
+import * as path from "path";
 // eslint-disable-next-line @typescript-eslint/no-require-imports
 import stripAnsi = require("strip-ansi");
 import configuration from "./configuration";
@@ -149,7 +150,24 @@ export class DiagnosticsManager implements vscode.Disposable {
                 typeof diagnostic.code !== "string" &&
                 typeof diagnostic.code !== "number"
             ) {
-                if (diagnostic.code.target.fsPath.endsWith(".md")) {
+                const fsPath = diagnostic.code.target.fsPath;
+
+                // Work around a bug in the nightlies where the URL comes back looking like:
+                // `/path/to/TestPackage/https:/docs.swift.org/compiler/documentation/diagnostics/nominal-types`
+                // Transform this in to a valid docs.swift.org URL which the openEducationalNote command
+                // will open in a browser.
+                // FIXME: This can be removed when the bug is fixed in sourcekit-lsp.
+                let open = false;
+                const needle = `https:${path.sep}docs.swift.org${path.sep}`;
+                if (fsPath.indexOf(needle) !== -1) {
+                    const extractedPath = `https://docs.swift.org/${fsPath.split(needle).pop()}/`;
+                    diagnostic.code.target = vscode.Uri.parse(extractedPath.replace(/\\/g, "/"));
+                    open = true;
+                } else if (diagnostic.code.target.fsPath.endsWith(".md")) {
+                    open = true;
+                }
+
+                if (open) {
                     diagnostic.code = {
                         target: vscode.Uri.parse(
                             `command:swift.openEducationalNote?${encodeURIComponent(JSON.stringify(diagnostic.code.target))}`
diff --git a/src/commands/openEducationalNote.ts b/src/commands/openEducationalNote.ts
index ea3dbe677..9f5e75b91 100644
--- a/src/commands/openEducationalNote.ts
+++ b/src/commands/openEducationalNote.ts
@@ -20,5 +20,9 @@ import * as vscode from "vscode";
  * The default behaviour is to open it in a markdown preview to the side.
  */
 export async function openEducationalNote(markdownFile: vscode.Uri | undefined): Promise<void> {
-    await vscode.commands.executeCommand("markdown.showPreviewToSide", markdownFile);
+    if (markdownFile?.fsPath.endsWith(".md")) {
+        await vscode.commands.executeCommand("markdown.showPreviewToSide", markdownFile);
+    } else if (markdownFile !== undefined) {
+        await vscode.env.openExternal(markdownFile);
+    }
 }
diff --git a/test/integration-tests/DiagnosticsManager.test.ts b/test/integration-tests/DiagnosticsManager.test.ts
index 7f17dffe3..473b6802c 100644
--- a/test/integration-tests/DiagnosticsManager.test.ts
+++ b/test/integration-tests/DiagnosticsManager.test.ts
@@ -690,6 +690,45 @@ suite("DiagnosticsManager Test Suite", function () {
                     assert.fail("Diagnostic target not replaced with markdown command");
                 }
             });
+
+            test("target with malformed nightly link", async () => {
+                const malformedUri =
+                    "/path/to/TestPackage/https:/docs.swift.org/compiler/documentation/diagnostics/nominal-types";
+                const expectedUri =
+                    "https://docs.swift.org/compiler/documentation/diagnostics/nominal-types/";
+                diagnostic.code = {
+                    value: "string",
+                    target: vscode.Uri.file(malformedUri),
+                };
+
+                workspaceContext.diagnostics.handleDiagnostics(
+                    mainUri,
+                    DiagnosticsManager.isSourcekit,
+                    [diagnostic]
+                );
+
+                const diagnostics = vscode.languages.getDiagnostics(mainUri);
+                const matchingDiagnostic = diagnostics.find(findDiagnostic(diagnostic));
+
+                expect(matchingDiagnostic).to.have.property("code");
+                expect(matchingDiagnostic?.code).to.have.property("value", "More Information...");
+
+                if (
+                    matchingDiagnostic &&
+                    matchingDiagnostic.code &&
+                    typeof matchingDiagnostic.code !== "string" &&
+                    typeof matchingDiagnostic.code !== "number"
+                ) {
+                    expect(matchingDiagnostic.code.target.scheme).to.equal("command");
+                    expect(matchingDiagnostic.code.target.path).to.equal(
+                        "swift.openEducationalNote"
+                    );
+                    const parsed = JSON.parse(matchingDiagnostic.code.target.query);
+                    expect(vscode.Uri.from(parsed).toString()).to.equal(expectedUri);
+                } else {
+                    assert.fail("Diagnostic target not replaced with markdown command");
+                }
+            });
         });
 
         suite("keepAll", () => {