diff --git a/ggml-cuda/mmq.cuh b/ggml-cuda/mmq.cuh
index 62677981c..e2d07c202 100644
--- a/ggml-cuda/mmq.cuh
+++ b/ggml-cuda/mmq.cuh
@@ -2071,15 +2071,18 @@ static __global__ void mul_mat_q_stream_k_fixup(
     const int bidx_stop  = (blockIdx.y*nty + blockIdx.x + 1) * block_num_mmq / (gridDim.y*gridDim.x) + 1;
 
     for (int bidx = bidx_start; bidx < bidx_stop; ++bidx) {
-        const int64_t kb_stop = GGML_PAD((int64_t)(bidx + 1)*blocks_per_ne00*ntx*nty / block_num_mmq, blocks_per_warp);
+        const int64_t kbc      = GGML_PAD((int64_t) bidx     *blocks_per_ne00*ntx*nty / block_num_mmq, blocks_per_warp);
+        const int64_t kbc_stop = GGML_PAD((int64_t)(bidx + 1)*blocks_per_ne00*ntx*nty / block_num_mmq, blocks_per_warp);
 
-        if (kb_stop % blocks_per_ne00 == 0) {
+        // Skip fixup tile if the MMQ CUDA block never wrote anything to it:
+        if (kbc == kbc_stop || kbc_stop % blocks_per_ne00 == 0) {
             continue;
         }
 
-        const int jt =  kb_stop /    (blocks_per_ne00*nty);
-        const int it = (kb_stop - jt*(blocks_per_ne00*nty)) / blocks_per_ne00;
+        const int jt =  kbc_stop /    (blocks_per_ne00*nty);
+        const int it = (kbc_stop - jt*(blocks_per_ne00*nty)) / blocks_per_ne00;
 
+        // Skip fixup tile if it's unrelated to the output tile assigned to this CUDA block:
         if (it != blockIdx.x || jt != blockIdx.y) {
             continue;
         }