diff --git a/lib/blockchain/chain.js b/lib/blockchain/chain.js
index 204fbb98..4e5f53e8 100644
--- a/lib/blockchain/chain.js
+++ b/lib/blockchain/chain.js
@@ -979,18 +979,14 @@ class Chain extends AsyncEmitter {
           tip.height - fork.height
         );
 
-        // mark invalid_child from tip of fork to second block of fork
-        while (competitor.height > fork.height + 2) {
+        // mark invalid_child from tip of fork to first block of fork
+        while (competitor.height !== fork.height + 1) {
           const previous = await this.getPrevious(competitor)
           await this.invalidate(previous.hash)
         }
 
-        // mark invalid first block of fork
-        const previous = await this.getPrevious(competitor)
-        await this.invalidate(previous.hash)
-
         // check
-        assert.equal(this.getPrevious(previous), fork, 'nlr invalidation down to the fork')
+        assert.equal(await this.getPrevious(competitor), fork, 'nlr invalidation down to the fork')
 
         return true
       }