fix: revert removal of FE workaround

client/src/components/Metrics/MetricsEpoch/MetricsEpochGridFundsUsage/MetricsEpochGridFundsUsage.tsx

@@ -35,7 +35,13 @@ const MetricsEpochGridFundsUsage: FC<MetricsEpochGridFundsUsageProps> = ({
 
   const projectCosts = epochInfo ? epochInfo.operationalCost : BigInt(0);
   const staking = epochInfo ? epochInfo.staking : BigInt(0);
-  const ppf = epochInfo ? epochInfo.ppf : BigInt(0);
+  // const ppf = epochInfo ? epochInfo.ppf : BigInt(0);
+  /**
+   * WORKAROUND
+   * Temporary ppf forced by backend changes. Correct formula above!
+   * TODO OCT-1567: https://linear.app/golemfoundation/issue/OCT-1567/restore-correct-ppf-formula-in-client
+   */
+  const ppf = epoch === 3 && epochInfo ? epochInfo.ppf - epochInfo.individualRewards : BigInt(0);
   const communityFund = epochInfo ? epochInfo.communityFund : BigInt(0);
 
   const donatedToProjects = epochInfo
@@ -48,7 +54,17 @@ const MetricsEpochGridFundsUsage: FC<MetricsEpochGridFundsUsageProps> = ({
     if (!epochInfo) {
       return BigInt(0);
     }
+    /**
+     * epochInfo.ppf includes epochInfo.individualRewards.
+     * Half of PPF goes to the users to manage.
+     * Half of PPR goes to "PPF" section.
+     */
     if (epoch === 3) {
+      /**
+       * WORKAROUND
+       * Temporary ppf forced by backend changes. Correct formula above!
+       * TODO OCT-1567: https://linear.app/golemfoundation/issue/OCT-1567/restore-correct-ppf-formula-in-client
+       */
       return (
         ppf / 2n + epochInfo.individualRewards - totalUserDonationsWithPatronRewards - unusedRewards
       );