diff --git a/test/null/test_uops.py b/test/null/test_uops.py
index 247c611250..94569476ce 100644
--- a/test/null/test_uops.py
+++ b/test/null/test_uops.py
@@ -55,11 +55,11 @@ class TestDTypeFromUOp(unittest.TestCase):
     invalid = UOp.invalid()
     self.assertIs(invalid.dtype, dtypes.bool)
     self.assertIs(UOp.const(Invalid, dtypes.float32), invalid)
-    self.assertIs((moved:=invalid.reshape((1,))).cast(dtypes.float32), moved)
     scratch = Tensor.invalids(4, dtype=dtypes.float32)
     self.assertEqual((scratch.dtype, next(u.dtype for u in scratch.uop.toposort() if u.op is Ops.BUFFER), next(u.dtype for u in scratch.uop.toposort()
       if u.is_invalid)), (dtypes.float32, dtypes.float32, dtypes.bool))
     invalid, value = UOp.invalid(), UOp.const(1, dtypes.float32)
+    for u in (UOp.param(0, dtypes.bool, ()).where(value, invalid), value+invalid, UOp.stack(value, invalid)): self.assertIs(u.src[-1], invalid)
     for u in (UOp(Ops.STACK, dtypes.float32, src=(value, invalid)), UOp(Ops.ADD, dtypes.float32, src=(value, invalid)),
               UOp.const(True).where(value, invalid), UOp(Ops.CMPLT, src=(invalid, value)), UOp(Ops.CMPLT, src=(value, invalid)),
               UOp.param(0, dtypes.float32, (4,)).index(invalid)): type_verify(u, spec_shared)
diff --git a/tinygrad/mixin/dtype.py b/tinygrad/mixin/dtype.py
index 08d112da74..b46bac675b 100644
--- a/tinygrad/mixin/dtype.py
+++ b/tinygrad/mixin/dtype.py
@@ -30,7 +30,7 @@ class DTypeMixin:
     print(t.dtype, t.numpy())
     ```
     """
-    return self if self.dtype == (dt:=to_dtype(dtype)) or self._uop.base.is_invalid else self._wrap_uop(self._uop.alu(Ops.CAST, arg=dt))
+    return self if self.dtype == (dt:=to_dtype(dtype)) else self._wrap_uop(self._uop.alu(Ops.CAST, arg=dt))
 
   def bitcast(self, dtype:DTypeLike) -> Self:
     """
diff --git a/tinygrad/mixin/elementwise.py b/tinygrad/mixin/elementwise.py
index b6f19facfd..aa746bb454 100644
--- a/tinygrad/mixin/elementwise.py
+++ b/tinygrad/mixin/elementwise.py
@@ -24,6 +24,7 @@ class ElementwiseMixin(CreationMixin):
     out_dtype = least_upper_dtype(x.dtype, y.dtype)
     # keep weak CONST weak, might lift weakint -> weakfloat
     def promote(t):
+      if t._uop.base.is_invalid: return t  # invalid bool is weak const
       if t.dtype in dtypes.weaks and t._uop.base.op is Ops.CONST: return t._wrap_uop(t._uop.const_like(t._uop.base.val, weak_dtype(out_dtype)))
       return t.cast(out_dtype)
     return promote(x), promote(y)
diff --git a/tinygrad/uop/ops.py b/tinygrad/uop/ops.py
index 4f8eabd954..ccf39be4dc 100644
--- a/tinygrad/uop/ops.py
+++ b/tinygrad/uop/ops.py
@@ -801,7 +801,8 @@ class UOp(RandMixin, metaclass=UOpMetaClass):
         # arg is the other srcs; all are cast to the promoted dtype, spec requires STACK srcs to match its dtype
         srcs = (self,)+tuple(arg)
         dtype = cast(DType, dtype_from_uop(Ops.STACK, srcs, None))
-        return UOp(Ops.STACK, dtype, tuple(u.cast(dtype) for u in srcs))
+        # TODO: why cast here?
+        return UOp(Ops.STACK, dtype, tuple(u if u.base.is_invalid else u.cast(dtype) for u in srcs))
       case _: raise RuntimeError(f"{op} is not a MovementOp")
     usrcs = [shape_to_shape_arg(arg) for arg in src_args]
     if len(usrcs) == 0: return UOp(op, src=(self,), arg=arg)
@@ -1762,7 +1763,7 @@ def lower_weak_node(u:UOp) -> UOp|None:
   if src == u.src or any(s.dtype in dtypes.weaks for s in src[start:]): return None
   dt = strong_dtype(least_upper_dtype(select_dtype(u), *(s.dtype for s in src)) if u.op in GroupOp.Binary
                     else unwrap(dtype_from_uop(u.op, src, u.arg)))
-  return u.replace(dtype=None, src=src[:start]+tuple(s.cast(dt) for s in src[start:])).cast(u.dtype)
+  return u.replace(dtype=None, src=src[:start]+tuple(s if s.base.is_invalid else s.cast(dt) for s in src[start:])).cast(u.dtype)
 pm_lower_weak = PatternMatcher([
   (UPat(Ops.CONST, dtype=dtypes.weaks, name="u"), lambda u: UOp.const(u.val, select_dtype(u)).cast(u.dtype)),
   # two stacked weak casts are a weakint value used as weakfloat (or vice versa): resolve the inner one at the outer kind's default.