Don't adjust width of infill. It produces dangerously wide fills.

If the infill flow adjustment is enabled, report cases,
where the infill flow grows over the limits.
Make the internal bridging infill 50% sparse.

lib/Slic3r/Fill/Rectilinear.pm

@@ -31,11 +31,15 @@ sub fill_surface {
     
     # define flow spacing according to requested density
     if ($params{density} == 1 && !$params{dont_adjust}) {
+        my $old_spacing = $self->spacing;
         $self->_line_spacing($self->adjust_solid_spacing(
             width       => $bounding_box->size->x,
             distance    => $self->_line_spacing,
         ));
         $self->spacing(unscale $self->_line_spacing);
+        if (abs($old_spacing - $self->spacing) > 0.3 * $old_spacing) {
+            print "Infill2: Extreme spacing adjustment, from: ", $old_spacing, " to: ", $self->spacing, "\n";
+        }
     } else {
         # extend bounding box so that our pattern will be aligned with other layers
         $bounding_box->merge_point(Slic3r::Point->new(