diff --git a/Source/Diagnostics/FlushFormats/FlushFormatOpenPMD.cpp b/Source/Diagnostics/FlushFormats/FlushFormatOpenPMD.cpp
index e15a7065f3a..ef897f8d3a0 100644
--- a/Source/Diagnostics/FlushFormats/FlushFormatOpenPMD.cpp
+++ b/Source/Diagnostics/FlushFormats/FlushFormatOpenPMD.cpp
@@ -154,9 +154,11 @@ FlushFormatOpenPMD::WriteToFile (
     // Set step and output directory name.
     m_OpenPMDPlotWriter->SetStep(output_iteration, prefix, file_min_digits, isBTD);
 
-    // fields: only dumped for coarse level
-    m_OpenPMDPlotWriter->WriteOpenPMDFieldsAll(
-        varnames, mf, geom, output_levels, output_iteration, static_cast<amrex::Real>(time), isBTD, full_BTD_snapshot);
+    if (!mf.empty()) {
+        // fields: only dumped for coarse level
+        m_OpenPMDPlotWriter->WriteOpenPMDFieldsAll(
+            varnames, mf, geom, output_levels, output_iteration, static_cast<amrex::Real>(time), isBTD, full_BTD_snapshot);
+    }
 
     // particles: all (reside only on locally finest level)
     m_OpenPMDPlotWriter->WriteOpenPMDParticles(
diff --git a/Source/Diagnostics/RecordingPlaneDiagnostics.cpp b/Source/Diagnostics/RecordingPlaneDiagnostics.cpp
index f388f051a80..b25acacdb74 100644
--- a/Source/Diagnostics/RecordingPlaneDiagnostics.cpp
+++ b/Source/Diagnostics/RecordingPlaneDiagnostics.cpp
@@ -393,7 +393,7 @@ RecordingPlaneDiagnostics::Flush (int i_buffer, bool /* force_flush */)
         bool const plot_raw_fields_guards = false;
 
         if (nparticles > 0) {
-            m_flush_format->WriteToFile(m_varnames, m_mf_output[i_buffer], m_geom_output[i_buffer],
+            m_flush_format->WriteToFile(m_varnames, {}, m_geom_output[i_buffer],
                                         warpx.getistep(), warpx.gett_new(0), m_output_species[i_buffer], nlev_output, m_file_prefix,
                                         m_file_min_digits, plot_raw_fields, plot_raw_fields_guards, use_pinned_pc,
                                         isBTD, i_buffer, m_flush_counter, maxBTDBuffers, geom,