Can compute order(Q) but not collect(Q) for f.p. group

[thofma]

My obligatory question on finitely presented groups for this week. I have the following situation, where I can compute the order, but not the elements, of an f.p. group. Is there any trick to make this work?

julia> F = free_group(2);

julia> x, y = gens(F);

julia> rels = [y^-2*x^-4*y^-2*x^4, y^4*x^-1*y*x^5*y^-5*x^-4*y^4*x];

julia> Q, = quo(F, rels);

julia> order(Q)
36

julia> collect(Q)
ERROR: Error thrown by GAP: Error, the coset enumeration has defined more than 4096000 cosets
 at /artifacts/7a7471c3a274d605d85c06775fcb6f9962114ff7/share/gap/lib/grpfp.gi:1224 called from

[ThomasBreuer]

First I thought that this might be another example where we know the order of a finitely presented group, but where it is hard to find a faithful permutation representation.
However, this is not really the case.
(Thus you can ask for isomorphism(PermGroup, Q), compute the elements in the image, and map them back to Q if necessary; the computation of the isomorphism takes some time.)

I do not understand why the GAP function called by collect runs into the above coset enumeration problem; I will ask the GAP experts ...