`VoleRefiner.DigraphTransporter` isn't working properly

[wilfwilson]

gap> D := CycleDigraph(5);;
gap> con_stab := VoleCon.Stabilize(D, OnDigraphs);;
gap> con_trans := VoleCon.Transport(D, D, OnDigraphs);;
gap> VoleFind.Rep(con_stab);
(1,4,2,5,3)
gap> VoleFind.Rep(con_trans);
Error, There was a fatal error in vole: Invalid problem specification. Does one of your constraints have the wrong ar\
gument type? at /Users/Wilf/GAP/pkg/vole/gap/internal/comms.gi:311 called from
_Vole.ExecuteVole( rec(
    config := rec(
        points := points,
        find_coset := find_coset,
        find_canonical := find_canonical,
        root_search := root_search,
        search_config := rec(
            full_graph_refine := false,
            find_single := find_single ) ),
    constraints := constraints ), gapcons, canonical_group
 ) at /Users/Wilf/GAP/pkg/vole/gap/internal/comms.gi:409 called from
_Vole.Solve( points, false, true, false, constraints, false, false
 ) at /Users/Wilf/GAP/pkg/vole/gap/internal/comms.gi:452 called from
_Vole.CosetSolve( Minimum( bounds.min, bounds.max ), constraints
 ) at /Users/Wilf/GAP/pkg/vole/gap/interface.gi:18 called from
<function "VoleFind.Rep">( <arguments> )
 called from read-eval loop at *stdin*:19
type 'quit;' to quit to outer loop

[wilfwilson]

It's possible that I'm misunderstanding something, or that I have assumed something incorrect about the internal digraph format; currently VoleCon.Transport is converting a Digraphs package object into a list of lists by calling OutNeighbours on it, and then passing that to VoleRefiner.DigraphTransporter.