diff --git a/packages/worker/src/app.service.ts b/packages/worker/src/app.service.ts
index 71d82079e..f0fbaa830 100644
--- a/packages/worker/src/app.service.ts
+++ b/packages/worker/src/app.service.ts
@@ -15,6 +15,7 @@ import { SystemContractService } from "./contract/systemContract.service";
 @Injectable()
 export class AppService implements OnModuleInit, OnModuleDestroy {
   private readonly logger: Logger;
+  private isHandlingBlocksRevert = false;
 
   public constructor(
     private readonly counterService: CounterService,
@@ -43,6 +44,11 @@ export class AppService implements OnModuleInit, OnModuleDestroy {
 
   @OnEvent(BLOCKS_REVERT_DETECTED_EVENT)
   protected async handleBlocksRevert({ detectedIncorrectBlockNumber }: { detectedIncorrectBlockNumber: number }) {
+    if (this.isHandlingBlocksRevert) {
+      return;
+    }
+    this.isHandlingBlocksRevert = true;
+
     this.logger.log("Stopping workers before blocks revert");
     await this.stopWorkers();
 
@@ -50,7 +56,9 @@ export class AppService implements OnModuleInit, OnModuleDestroy {
     await this.blocksRevertService.handleRevert(detectedIncorrectBlockNumber);
 
     this.logger.log("Starting workers after blocks revert");
-    await this.startWorkers();
+    this.startWorkers();
+
+    this.isHandlingBlocksRevert = false;
   }
 
   private startWorkers() {
diff --git a/packages/worker/src/block/block.watcher.ts b/packages/worker/src/block/block.watcher.ts
index f491c6554..0ae3f5978 100644
--- a/packages/worker/src/block/block.watcher.ts
+++ b/packages/worker/src/block/block.watcher.ts
@@ -119,7 +119,7 @@ export class BlockWatcher implements OnModuleInit, OnModuleDestroy {
     this.logger.debug(`Last block number is set to: ${this.lastBlockchainBlockNumber}`);
 
     this.blockchainService.on("block", (blockNumber) => {
-      this.lastBlockchainBlockNumber = Math.max(this.lastBlockchainBlockNumber, blockNumber);
+      this.lastBlockchainBlockNumber = blockNumber || this.lastBlockchainBlockNumber;
       this.blockchainBlocksMetric.set(this.lastBlockchainBlockNumber);
       this.logger.debug(`Last block number is updated to: ${this.lastBlockchainBlockNumber}`);
     });
diff --git a/packages/worker/src/contract/systemContract.service.spec.ts b/packages/worker/src/contract/systemContract.service.spec.ts
index 8e07ebaa9..6359fddd7 100644
--- a/packages/worker/src/contract/systemContract.service.spec.ts
+++ b/packages/worker/src/contract/systemContract.service.spec.ts
@@ -45,15 +45,15 @@ describe("SystemContractService", () => {
         SystemContractService.getSystemContracts().map((contract) => mock<Address>({ address: contract.address }))
       );
       await systemContractService.addSystemContracts();
-      expect(addressRepositoryMock.add).toBeCalledTimes(0);
+      expect(addressRepositoryMock.upsert).toBeCalledTimes(0);
     });
 
     it("adds all system contracts if none of them exist in the DB", async () => {
       (addressRepositoryMock.find as jest.Mock).mockResolvedValue([]);
       await systemContractService.addSystemContracts();
-      expect(addressRepositoryMock.add).toBeCalledTimes(systemContracts.length);
+      expect(addressRepositoryMock.upsert).toBeCalledTimes(systemContracts.length);
       for (const systemContract of systemContracts) {
-        expect(addressRepositoryMock.add).toBeCalledWith({
+        expect(addressRepositoryMock.upsert).toBeCalledWith({
           address: systemContract.address,
           bytecode: `${systemContract.address}-code`,
         });
@@ -69,10 +69,10 @@ describe("SystemContractService", () => {
         existingContractAddresses.map((existingContractAddress) => mock<Address>({ address: existingContractAddress }))
       );
       await systemContractService.addSystemContracts();
-      expect(addressRepositoryMock.add).toBeCalledTimes(systemContracts.length - existingContractAddresses.length);
+      expect(addressRepositoryMock.upsert).toBeCalledTimes(systemContracts.length - existingContractAddresses.length);
       for (const systemContract of systemContracts) {
         if (!existingContractAddresses.includes(systemContract.address)) {
-          expect(addressRepositoryMock.add).toBeCalledWith({
+          expect(addressRepositoryMock.upsert).toBeCalledWith({
             address: systemContract.address,
             bytecode: `${systemContract.address}-code`,
           });
@@ -93,10 +93,10 @@ describe("SystemContractService", () => {
         return `${address}-code`;
       });
       await systemContractService.addSystemContracts();
-      expect(addressRepositoryMock.add).toBeCalledTimes(systemContracts.length - notDeployedSystemContracts.length);
+      expect(addressRepositoryMock.upsert).toBeCalledTimes(systemContracts.length - notDeployedSystemContracts.length);
       for (const systemContract of systemContracts) {
         if (!notDeployedSystemContracts.includes(systemContract.address)) {
-          expect(addressRepositoryMock.add).toBeCalledWith({
+          expect(addressRepositoryMock.upsert).toBeCalledWith({
             address: systemContract.address,
             bytecode: `${systemContract.address}-code`,
           });
diff --git a/packages/worker/src/contract/systemContract.service.ts b/packages/worker/src/contract/systemContract.service.ts
index 09a8b9304..d6b10b1c8 100644
--- a/packages/worker/src/contract/systemContract.service.ts
+++ b/packages/worker/src/contract/systemContract.service.ts
@@ -26,7 +26,7 @@ export class SystemContractService {
         const bytecode = await this.blockchainService.getCode(contract.address);
         // some contract might not exist on the environment yet
         if (bytecode !== "0x") {
-          await this.addressRepository.add({
+          await this.addressRepository.upsert({
             address: contract.address,
             bytecode,
           });