When using HTML table and port, arrows are sometimes misplaced

The following example should draw 3 nodes with 2 edges.

@startuml
digraph unix {

sh0004 [shape=rect,label="4"];
sh0005 [shape=rect,label=<<TABLE BORDER="0" CELLBORDER="0" CELLSPACING="0" CELLPADDING="0"><TR><TD></TD><TD FIXEDSIZE="TRUE" WIDTH="1.0" HEIGHT="18"></TD><TD></TD></TR><TR><TD FIXEDSIZE="TRUE" WIDTH="22" HEIGHT="1"></TD><TD BGCOLOR="#0000bb" FIXEDSIZE="TRUE" WIDTH="18" HEIGHT="18" PORT="h"></TD><TD FIXEDSIZE="TRUE" WIDTH="22" HEIGHT="1"></TD></TR><TR><TD></TD><TD FIXEDSIZE="TRUE" WIDTH="1" HEIGHT="18"></TD><TD></TD></TR></TABLE>>];
sh0006 [shape=rect,label="6"];

#This link in red should have no arrow
sh0004->sh0005:h[arrowtail=none,arrowhead=none,minlen=0,color="#FF0000"];

#This link in gree should have one arrow
sh0005:h->sh0006[arrowtail=empty,arrowhead=none,arrowsize=0.5,minlen=0,color="#00FF00"];

}
@enduml

When generated with GraphViz 2.38.0:

• The first link (in red) has an arrow (it should not)
• The second link (in green) has no arrow (it should)