diff --git a/theories/bi/lib/fixpoint.v b/theories/bi/lib/fixpoint.v
index d02a740610a441cef0e0acc76a38ee78523f1999..7e8091e22aaff9fb077a3e0f3ba8a75c52176a65 100644
--- a/theories/bi/lib/fixpoint.v
+++ b/theories/bi/lib/fixpoint.v
@@ -14,11 +14,13 @@ Local Existing Instance bi_mono_pred_ne.
 
 Definition bi_least_fixpoint {PROP : bi} {A : ofeT}
     (F : (A → PROP) → (A → PROP)) (x : A) : PROP :=
-  (∀ Φ : A -n> PROP, <pers> (∀ x, F Φ x -∗ Φ x) → Φ x)%I.
+  tc_opaque (∀ Φ : A -n> PROP, <pers> (∀ x, F Φ x -∗ Φ x) → Φ x)%I.
+Arguments bi_least_fixpoint : simpl never.
 
 Definition bi_greatest_fixpoint {PROP : bi} {A : ofeT}
     (F : (A → PROP) → (A → PROP)) (x : A) : PROP :=
-  (∃ Φ : A -n> PROP, <pers> (∀ x, Φ x -∗ F Φ x) ∧ Φ x)%I.
+  tc_opaque (∃ Φ : A -n> PROP, <pers> (∀ x, Φ x -∗ F Φ x) ∧ Φ x)%I.
+Arguments bi_greatest_fixpoint : simpl never.
 
 Section least.
   Context {PROP : bi} {A : ofeT} (F : (A → PROP) → (A → PROP)) `{!BiMonoPred F}.
@@ -28,7 +30,7 @@ Section least.
 
   Lemma least_fixpoint_unfold_2 x : F (bi_least_fixpoint F) x ⊢ bi_least_fixpoint F x.
   Proof.
-    iIntros "HF" (Φ) "#Hincl".
+    rewrite /bi_least_fixpoint /=. iIntros "HF" (Φ) "#Hincl".
     iApply "Hincl". iApply (bi_mono_pred _ Φ with "[#]"); last done.
     iIntros "!#" (y) "Hy". iApply ("Hy" with "[# //]").
   Qed.