diff --git a/image_analysis/scale_merge/RotationScaleMergeGPU.cu b/image_analysis/scale_merge/RotationScaleMergeGPU.cu
index 15e3ebf7d..8ed922149 100644
--- a/image_analysis/scale_merge/RotationScaleMergeGPU.cu
+++ b/image_analysis/scale_merge/RotationScaleMergeGPU.cu
@@ -713,11 +713,15 @@ struct RotationScaleMergeGPU::Impl {
     // end and is asked for again - the same buffer, so what the merge computes does not depend on the
     // wait. It is asked for again also when nothing is running beside it any more: work that ended
     // between the failure and the check has just given its memory back.
+    //
+    // The failed allocation is handled here, so its error must not stay behind as this thread's last
+    // error: the next kernel launch's cudaGetLastError() would report it over work that went fine.
     template <typename T>
     CudaDevicePtr<T> Alloc(size_t n) const {
         try {
             return CudaDevicePtr<T>(n, ALLOC);
         } catch (const JFJochException &) {
+            cuda_clear_error();
         }
         if (!wait_for_gpu_work_beside(GPU_BUSY_TIMEOUT))
             ThrowGPUBusy(n_obs);