@@ -738,6 +738,54 @@ describe("assembleReleasePlan", () => {
         },
       ]);
     });
+
+    // https://github.com/changesets/changesets/issues/963
+    // https://github.com/changesets/changesets/issues/1759
+    it("should not bump fixed packages due to peer dependents", () => {
+      const setup = new FakeFullState({ changesets: [] });
+
+      setup.addPackage("@ex/core", "0.1.0");
+      setup.addPackage("@ex/errors", "0.1.0");
+      setup.addPackage("@ex/api", "0.1.0");
+      setup.addPackage("some-peer", "0.1.0"); // optional peer
+      setup.addPackage("@ex/components", "0.1.0");
+
+      setup.updateDependencies("@ex/api", [
+        { name: "@ex/core", range: "0.1.0" },
+        { name: "@ex/errors", range: "0.1.0" },
+        { name: "some-peer", range: "0.1.0", type: "peer" },
+      ]);
+      setup.updateDependencies("@ex/components", [
+        { name: "@ex/api", range: "0.1.0" },
+        { name: "some-peer", range: "0.1.0" },
+      ]);
+
+      setup.addChangeset({ releases: [{ name: "@ex/core", type: "minor" }] });
+
+      const result = assembleReleasePlan(
+        setup.changesets,
+        setup.packages,
+        {
+          ...defaultConfig,
+          fixed: [
+            [
+              "@ex/core",
+              "@ex/errors",
+              "@ex/api",
+              "some-peer",
+              "@ex/components",
+            ],
+          ],
+        },
+        undefined,
+      );
+
+      expect(result.releases).toHaveLength(5);
+      expect(
+        result.releases.every((release) => release.newVersion === "0.2.0"),
+        "every bump should be to 0.2.0",
+      ).toBe(true);
+    });
   });
 
   describe("pre mode", () => {
 
@@ -102,11 +102,32 @@ export class FakeFullState {
       (a) => a.packageJson.name === dependent,
     );
     if (!pkg) throw new Error(`No "${dependent}" package`);
-    if (!pkg.packageJson.dependencies) {
-      pkg.packageJson.dependencies = {};
-    }
+    pkg.packageJson.dependencies ??= {};
     pkg.packageJson.dependencies[dependency] = versionRange;
   }
+  updateDependencies(
+    dependent: string,
+    deps: Array<{
+      name: string;
+      range: string;
+      type?: "direct" | "peer" | "dev";
+    }>,
+  ) {
+    const pkg = this.packages.packages.find(
+      (p) => p.packageJson.name === dependent,
+    );
+    if (!pkg) throw new Error(`No "${dependent}" package`);
+    for (const { name, range, type } of deps) {
+      const property =
+        type === "dev"
+          ? "devDependencies"
+          : type === "peer"
+            ? "peerDependencies"
+            : "dependencies";
+      pkg.packageJson[property] ??= {};
+      pkg.packageJson[property][name] = range;
+    }
+  }
   updateDevDependency(
     dependent: string,
     dependency: string,
@@ -116,9 +137,7 @@ export class FakeFullState {
       (a) => a.packageJson.name === dependent,
     );
     if (!pkg) throw new Error(`No "${dependent}" package`);
-    if (!pkg.packageJson.devDependencies) {
-      pkg.packageJson.devDependencies = {};
-    }
+    pkg.packageJson.devDependencies ??= {};
     pkg.packageJson.devDependencies[dependency] = versionRange;
   }
   updatePeerDependency(
@@ -130,9 +149,7 @@ export class FakeFullState {
       (a) => a.packageJson.name === dependent,
     );
     if (!pkg) throw new Error(`No "${dependent}" package`);
-    if (!pkg.packageJson.peerDependencies) {
-      pkg.packageJson.peerDependencies = {};
-    }
+    pkg.packageJson.peerDependencies ??= {};
     pkg.packageJson.peerDependencies[dependency] = versionRange;
   }