diff --git a/yarn.config.cjs b/yarn.config.cjs
index 548f434d4b4..7786e1cea9f 100644
--- a/yarn.config.cjs
+++ b/yarn.config.cjs
@@ -32,9 +32,8 @@ module.exports = defineConfig({
       const isChildWorkspace = workspace.cwd !== '.';
       const isPrivate =
         'private' in workspace.manifest && workspace.manifest.private === true;
-      const workspaceDependencies = Yarn.dependencies({ workspace });
       const dependenciesByIdentAndType = getDependenciesByIdentAndType(
-        workspaceDependencies,
+        Yarn.dependencies({ workspace }),
       );
 
       // All packages must have a name.
@@ -232,8 +231,9 @@ module.exports = defineConfig({
 });
 
 /**
- * Construct a nested map of dependencies where the first layer is keyed by
- * dependency ident and the second layer is keyed by dependency type.
+ * Construct a nested map of dependencies. The inner layer categorizes
+ * instances of the same dependency by its location in the manifest; the outer
+ * layer categorizes the inner layer by the name of the dependency.
  *
  * @param {Dependency[]} dependencies - The list of dependencies to transform.
  * @returns {Map<string, Map<DependencyType, Dependency>>} The resulting map.
@@ -260,8 +260,10 @@ function getDependenciesByIdentAndType(dependencies) {
 }
 
 /**
- * Construct a nested map of dependencies where the first layer is keyed by
- * dependency ident and the second layer is keyed by dependency range.
+ * Construct a nested map of non-peer dependencies (`dependencies` and
+ * `devDependencies`). The inner layer categorizes instances of the same
+ * dependency by the version range specified; the outer layer categorizes the
+ * inner layer by the name of the dependency itself.
  *
  * @param {Dependency[]} dependencies - The list of dependencies to transform.
  * @returns {Map<string, Map<string, Dependency[]>>} The resulting map.
@@ -513,11 +515,11 @@ function expectDependenciesNotInBothProdAndDev(
 ) {
   for (const [
     dependencyIdent,
-    dependenciesByType,
+    dependencyInstancesByType,
   ] of dependenciesByIdentAndType.entries()) {
     if (
-      dependenciesByType.size > 1 &&
-      !dependenciesByType.has('peerDependencies')
+      dependencyInstancesByType.size > 1 &&
+      !dependencyInstancesByType.has('peerDependencies')
     ) {
       workspace.error(
         `\`${dependencyIdent}\` cannot be listed in both \`dependencies\` and \`devDependencies\``,
@@ -532,15 +534,13 @@ function expectDependenciesNotInBothProdAndDev(
  * listed in the workspace's `peerDependencies` and the version range satisfies
  * the current version of the controller package.
  *
- * The expectation in this case is that the client will instantiate B in
- * order to pass it into A. Therefore, it needs to list not only A as a
- * dependency, but also B. Additionally, the version of B that the client
- * is using with A needs to match the version that A itself is expecting
- * internally.
+ * The expectation in this case is that the client will instantiate B in order
+ * to pass it into A. Therefore, it needs to list not only A as a dependency,
+ * but also B. Additionally, the version of B that the client is using with A
+ * needs to match the version that A itself is expecting internally.
  *
- * Note that this constraint does not apply for packages that seem to
- * represent controller singletons but actually represent abstract
- * classes.
+ * Note that this constraint does not apply for packages that seem to represent
+ * instantiable controllers but actually represent abstract classes.
  *
  * @param {Yarn} Yarn - The Yarn "global".
  * @param {Workspace} workspace - The workspace to check.
@@ -552,28 +552,29 @@ function expectControllerDependenciesListedAsPeerDependencies(
   workspace,
   dependenciesByIdentAndType,
 ) {
-  for (const dependenciesByType of dependenciesByIdentAndType.values()) {
-    const dependency = dependenciesByType.get('dependencies');
-
-    if (dependency === undefined) {
+  for (const [
+    dependencyIdent,
+    dependencyInstancesByType,
+  ] of dependenciesByIdentAndType.entries()) {
+    if (!dependencyInstancesByType.has('dependencies')) {
       continue;
     }
 
-    const dependencyWorkspace = Yarn.workspace({ ident: dependency.ident });
+    const dependencyWorkspace = Yarn.workspace({ ident: dependencyIdent });
 
     if (
       dependencyWorkspace !== null &&
-      dependency.ident.endsWith('-controller') &&
-      dependency.ident !== '@metamask/base-controller' &&
-      dependency.ident !== '@metamask/polling-controller' &&
-      !dependenciesByType.has('peerDependencies')
+      dependencyIdent.endsWith('-controller') &&
+      dependencyIdent !== '@metamask/base-controller' &&
+      dependencyIdent !== '@metamask/polling-controller' &&
+      !dependencyInstancesByType.has('peerDependencies')
     ) {
       const dependencyWorkspaceVersion = new semver.SemVer(
         dependencyWorkspace.manifest.version,
       );
       expectWorkspaceField(
         workspace,
-        `peerDependencies["${dependency.ident}"]`,
+        `peerDependencies["${dependencyIdent}"]`,
         `^${dependencyWorkspaceVersion.major}.0.0`,
       );
     }
@@ -594,13 +595,16 @@ function expectConsistentDependenciesAndDevDependencies(Yarn) {
     Yarn.dependencies(),
   );
 
-  for (const dependencyRangesForIdent of nonPeerDependenciesByIdent.values()) {
-    const dependencyRanges = [...dependencyRangesForIdent.keys()].sort();
-    if (dependencyRangesForIdent.size > 1) {
-      for (const dependencies of dependencyRangesForIdent.values()) {
+  for (const [
+    dependencyIdent,
+    dependenciesByRange,
+  ] of nonPeerDependenciesByIdent.entries()) {
+    const dependencyRanges = [...dependenciesByRange.keys()].sort();
+    if (dependenciesByRange.size > 1) {
+      for (const dependencies of dependenciesByRange.values()) {
         for (const dependency of dependencies) {
           dependency.error(
-            `Expected version range for ${dependency.ident} (in ${
+            `Expected version range for ${dependencyIdent} (in ${
               dependency.type
             }) to be consistent across monorepo. Pick one: ${inspect(
               dependencyRanges,