diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 7f4c739836ad6627865764ad1449df51ec77ec3a..fb21bcf7ac275f59ce4505d4957e70452b344d7a 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -1703,6 +1703,12 @@ static void write_cfl_alphas(FRAME_CONTEXT *const frame_ctx, int skip, int ind,
     assert(signs[CFL_PRED_U] == CFL_SIGN_POS);
     assert(signs[CFL_PRED_V] == CFL_SIGN_POS);
   } else {
+    // Check for uninitialized signs
+    if (cfl_alpha_codes[ind][CFL_PRED_U] == 0)
+      assert(signs[CFL_PRED_U] == CFL_SIGN_POS);
+    if (cfl_alpha_codes[ind][CFL_PRED_V] == 0)
+      assert(signs[CFL_PRED_V] == CFL_SIGN_POS);
+
     // Write a symbol representing a combination of alpha Cb and alpha Cr.
     aom_write_symbol(w, ind, frame_ctx->cfl_alpha_cdf, CFL_ALPHABET_SIZE);