diff --git a/blocks-common/i-bem/__html/i-bem__html.bemhtml b/blocks-common/i-bem/__html/i-bem__html.bemhtml
index 4c047246..8e3ac1bd 100644
--- a/blocks-common/i-bem/__html/i-bem__html.bemhtml
+++ b/blocks-common/i-bem/__html/i-bem__html.bemhtml
@@ -388,13 +388,13 @@ default: {
                         var mixItem = mix[i];
 
                         if (!mixItem) continue;
-
-                        var hasItem = mixItem.block || mixItem.elem,
+                        var hasItem = (mixItem.block && (this.block !== v.block || mixItem.block !== this.block))
+                                || (this.elem && (!mixItem.elemMods && !mixItem.mods))
+                                || mixItem.elem ,
                             block = mixItem.block || mixItem._block || this.block,
                             elem = mixItem.elem || mixItem._elem || this.elem,
                             mods = mixItem.mods || this.mods,
                             elemMods = mixItem.elemMods || {};
-
                         hasItem && buf.push(' ');
                         BEM_.INTERNAL[hasItem? 'buildClasses' : 'buildModsClasses'](
                             block,
diff --git a/blocks-common/i-bem/__html/test/files/i-bem/gh-core-804.bemhtml b/blocks-common/i-bem/__html/test/files/i-bem/gh-core-804.bemhtml
new file mode 100644
index 00000000..e69de29b
diff --git a/blocks-common/i-bem/__html/test/files/i-bem/gh-core-804.html b/blocks-common/i-bem/__html/test/files/i-bem/gh-core-804.html
new file mode 100644
index 00000000..c61a5c6a
--- /dev/null
+++ b/blocks-common/i-bem/__html/test/files/i-bem/gh-core-804.html
@@ -0,0 +1 @@
+<div class="b1 b1_m1_v1"></div><div class="b1 b1_m1_v1"></div><div class="b1 b2 b2_m1_v1"></div><div class="b1__e1 b1"></div><div class="b2 b1__e1"></div><div class="b1 b1__e1"></div><div class="b1__e1 b1__e1_m1_v1"></div><div class="b1__e1 b1__e1_m1_v1"></div><div class="b1__e1 b1__e2 b1__e2_m2_v2"></div><div class="b1__e1 b1__e1_m1_v1 b1__e2 b1__e2_m2_v2"></div><div class="b1__e1 b1__e1_m1_v1 b1__e2"></div>
diff --git a/blocks-common/i-bem/__html/test/files/i-bem/gh-core-804.json b/blocks-common/i-bem/__html/test/files/i-bem/gh-core-804.json
new file mode 100644
index 00000000..3c9f2dd0
--- /dev/null
+++ b/blocks-common/i-bem/__html/test/files/i-bem/gh-core-804.json
@@ -0,0 +1,60 @@
+[
+{
+  "block": "b1",
+  "mix": {
+    "block": "b1",
+    "mods": { "m1": "v1" }
+  }
+},
+{
+  "block": "b1",
+  "mix": {"mods": {"m1": "v1"}}
+},
+{
+  "block": "b1",
+  "mix": {
+    "block": "b2",
+    "mods": { "m1": "v1" }
+  }
+},
+{
+  "block": "b1",
+  "elem": "e1",
+  "mix": [{ "block": "b1" }]
+},
+{
+  "block": "b2",
+  "mix": [{ "block": "b1", "elem": "e1" }]
+},
+{
+  "block": "b1",
+  "mix": {"elem": "e1"}
+},
+{
+  "block": "b1",
+  "elem": "e1",
+  "mix": {"elemMods": {"m1": "v1"}}
+},
+{
+  "block": "b1",
+  "elem": "e1",
+  "mix": {"mods": {"m1": "v1"}}
+},
+{
+  "block": "b1",
+  "elem": "e1",
+  "mix": {"elem": "e2", "elemMods": {"m2": "v2"}}
+},
+{
+  "block": "b1",
+  "elem": "e1",
+  "elemMods": {"m1": "v1"},
+  "mix": {"elem": "e2", "elemMods": {"m2": "v2"}}
+},
+{
+  "block": "b1",
+  "elem": "e1",
+  "elemMods": {"m1": "v1"},
+  "mix": {"elem": "e2"}
+}
+]
diff --git a/blocks-common/i-bem/__html/test/i-bem-test.js b/blocks-common/i-bem/__html/test/i-bem-test.js
index ec3462a0..5b6a01ff 100644
--- a/blocks-common/i-bem/__html/test/i-bem-test.js
+++ b/blocks-common/i-bem/__html/test/i-bem-test.js
@@ -47,6 +47,7 @@ suite('i-bem block and others', function() {
   unit('simple types regression #254', 'gh-254');
   unit('applyNext in content regression #289', 'gh-289');
   unit('mods redefinition #550', 'gh-550');
+  unit('mix elem on same block', 'gh-core-804');
   unit('block with escaping this', 'escaping-this');
 
   test('re-entrance', function() {