Rebuild current and gather buffer masks during regrid (#6412)

This might fix #6390.

Author: atmyers

Source/Parallelization/WarpXRegrid.cpp

@@ -293,12 +293,6 @@ WarpX::RemakeLevel (int lev, Real /*time*/, const BoxArray& ba, const Distributi
 #endif
         }
 
-        if (lev > 0 && (n_field_gather_buffer > 0 || n_current_deposition_buffer > 0)) {
-            if (current_buffer_masks[lev] || gather_buffer_masks[lev]) {
-                BuildBufferMasks();
-            }
-        }
-
         // Re-initialize the lattice element finder with the new ba and dm.
         m_accelerator_lattice[lev]->InitElementFinder(lev, gamma_boost, gett_new(), ba, dm);
 
@@ -315,6 +309,18 @@ WarpX::RemakeLevel (int lev, Real /*time*/, const BoxArray& ba, const Distributi
 
         SetDistributionMap(lev, dm);
 
+        if (lev > 0 && (n_field_gather_buffer > 0 || n_current_deposition_buffer > 0)) {
+            if (current_buffer_masks[lev] || gather_buffer_masks[lev]) {
+                if (current_buffer_masks[lev]) {
+                    RemakeMultiFab( current_buffer_masks[lev] );
+                }
+                if (gather_buffer_masks[lev]) {
+                    RemakeMultiFab( gather_buffer_masks[lev] );
+                }
+                BuildBufferMasks();
+            }
+        }
+
     } else
     {
         WARPX_ABORT_WITH_MESSAGE("RemakeLevel: to be implemented");