diff --git a/postgraphiql/src/components/PostGraphiQL.js b/postgraphiql/src/components/PostGraphiQL.js
index c178de9fb6..b8dfccd423 100644
--- a/postgraphiql/src/components/PostGraphiQL.js
+++ b/postgraphiql/src/components/PostGraphiQL.js
@@ -95,13 +95,13 @@ function explainOptionRequiresAnalyze(option) {
   return ['wal', 'timing'].includes(option);
 }
 
-function buildExplainOptionsHeader(explainOptions) {
+function buildExplainOptionsString(explainOptions) {
   const analyzeEnabled = explainOptions.analyze;
-  const validOptions = Object.fromEntries(
-    Object.entries(explainOptions).filter(
-      ([option]) => !explainOptionRequiresAnalyze(option) || analyzeEnabled,
-    ),
-  );
+  const validOptions = analyzeEnabled
+    ? explainOptions
+    : Object.fromEntries(
+        Object.entries(explainOptions).filter(([option]) => !explainOptionRequiresAnalyze(option)),
+      );
   return querystring.stringify(validOptions, ';', '=');
 }
 
@@ -407,6 +407,7 @@ class PostGraphiQL extends React.PureComponent {
    */
   executeQuery = async graphQLParams => {
     const extraHeaders = this.getHeaders();
+    const explainOpts = buildExplainOptionsString(this.state.explainOptions);
     const response = await fetch(POSTGRAPHILE_CONFIG.graphqlUrl, {
       method: 'POST',
       headers: Object.assign(
@@ -414,11 +415,7 @@ class PostGraphiQL extends React.PureComponent {
           Accept: 'application/json',
           'Content-Type': 'application/json',
           ...(this.state.explain && POSTGRAPHILE_CONFIG.allowExplain
-            ? {
-                'X-PostGraphile-Explain': `on;${buildExplainOptionsHeader(
-                  this.state.explainOptions,
-                )}`,
-              }
+            ? { 'X-PostGraphile-Explain': explainOpts ? `on;${explainOpts}` : 'on' }
             : null),
         },
         extraHeaders,
diff --git a/scripts/dev b/scripts/dev
index d5e79ad075..169012528a 100755
--- a/scripts/dev
+++ b/scripts/dev
@@ -38,7 +38,7 @@ trap 'trap - SIGINT SIGTERM EXIT; JOBS="$(jobs -p)"; [[ "$JOBS" != "" ]] && kill
 
 # Run `react-scripts` in the GraphiQL directory as well parallel, but pipe the
 # output to `/dev/null`.
-#(sleep 1 && cd postgraphiql && PORT=5783 node_modules/.bin/react-scripts start) > /dev/null &
+(sleep 1 && cd postgraphiql && PORT=5783 node_modules/.bin/react-scripts start) > /dev/null &
 
 wait %1
 kill %2
diff --git a/src/postgraphile/http/createPostGraphileHttpRequestHandler.ts b/src/postgraphile/http/createPostGraphileHttpRequestHandler.ts
index 3c860d79c3..28b9b74907 100644
--- a/src/postgraphile/http/createPostGraphileHttpRequestHandler.ts
+++ b/src/postgraphile/http/createPostGraphileHttpRequestHandler.ts
@@ -166,7 +166,7 @@ function withPostGraphileContextFromReqResGenerator(
         jwtToken,
         pgSettings,
         explain: explainHeader && explainHeader.on,
-        explainOptions: explainHeader?.options ?? {},
+        explainOptions: (explainHeader && explainHeader.options) || {},
         ...moreOptions,
       },
       context => {
diff --git a/src/postgraphile/withPostGraphileContext.ts b/src/postgraphile/withPostGraphileContext.ts
index 3c9977fd7b..fd48889045 100644
--- a/src/postgraphile/withPostGraphileContext.ts
+++ b/src/postgraphile/withPostGraphileContext.ts
@@ -502,8 +502,10 @@ export function debugPgClient(pgClient: PoolClient, allowExplain = false): PoolC
               return null;
             }
             const plan = result
-              .map((r: any) => r[firstKey])
-              .map((r: any) => (typeof r === 'string' ? r : JSON.stringify(r, null, 2)))
+              .map((r: any) => {
+                const val = r[firstKey];
+                return typeof val === 'string' ? val : JSON.stringify(val, null, 2);
+              })
               .join('\n');
             return {
               ...rest,