diff --git a/src/OptimisticTokenVotingPlugin.sol b/src/OptimisticTokenVotingPlugin.sol
index 9a8a2a3..f79ea3f 100644
--- a/src/OptimisticTokenVotingPlugin.sol
+++ b/src/OptimisticTokenVotingPlugin.sol
@@ -208,7 +208,8 @@ contract OptimisticTokenVotingPlugin is
 
         // The last L2 block is too old
         TaikoData.Block memory _block = taikoL1.getBlock(_id - 1);
-        if (_block.proposedAt < (block.timestamp - governanceSettings.l2InactivityPeriod)) return false;
+        // proposedAt < (block.timestamp - l2InactivityPeriod), written as a sum
+        if ((_block.proposedAt + governanceSettings.l2InactivityPeriod) < block.timestamp) return false;
 
         return true;
     }
diff --git a/test/OptimisticTokenVotingPlugin.t.sol b/test/OptimisticTokenVotingPlugin.t.sol
index a00c964..73b3204 100644
--- a/test/OptimisticTokenVotingPlugin.t.sol
+++ b/test/OptimisticTokenVotingPlugin.t.sol
@@ -510,6 +510,32 @@ contract OptimisticTokenVotingPluginTest is AragonTest {
         assertEq(optimisticPlugin.isMember(randomWallet), false, "Random wallet should not be a member");
     }
 
+    function test_IsL2AvailableReturnsTheRightValues() public {
+        assertEq(optimisticPlugin.isL2Available(), true, "isL2Available should be true");
+
+        // paused
+        (, optimisticPlugin,,, votingToken,) = builder.withPausedTaikoL1().build();
+        assertEq(optimisticPlugin.isL2Available(), false, "isL2Available should be false");
+
+        // out of sync
+        (, optimisticPlugin,,, votingToken,) = builder.withOutOfSyncTaikoL1().build();
+        assertEq(optimisticPlugin.isL2Available(), false, "isL2Available should be false");
+
+        // out of sync: diff below lowerl2InactivityPeriod
+        setTime(5 minutes);
+        assertEq(optimisticPlugin.isL2Available(), true, "isL2Available should be true");
+
+        // out of sync: still within the period
+        setTime(50 days);
+        (, optimisticPlugin,,, votingToken,) = builder.withL2InactivityPeriod(50 days).build();
+        assertEq(optimisticPlugin.isL2Available(), true, "isL2Available should be true");
+
+        // out of sync: over
+        setTime(50 days + 1);
+        (, optimisticPlugin,,, votingToken,) = builder.withL2InactivityPeriod(50 days).build();
+        assertEq(optimisticPlugin.isL2Available(), false, "isL2Available should be false");
+    }
+
     // Create proposal
     function test_CreateProposalRevertsWhenCalledByANonProposer() public {
         switchTo(bob);
diff --git a/test/mocks/TaikoL1Mock.sol b/test/mocks/TaikoL1Mock.sol
index 9697f89..0657623 100644
--- a/test/mocks/TaikoL1Mock.sol
+++ b/test/mocks/TaikoL1Mock.sol
@@ -35,7 +35,7 @@ contract TaikoL1WithOldLastBlock is TaikoL1 {
     }
 
     function slotB() public pure override returns (TaikoData.SlotB memory result) {
-        result.numBlocks = 0;
+        result.numBlocks = 1;
     }
 
     function getBlock(uint64 _blockId) public pure override returns (TaikoData.Block memory result) {