I did use stepwise and {ic} as posted above.  Did I miss something?

> dePlot := DEplot3d(sys, [x(t), y(t), z(t)], t = 0 .. 10, {ic}, scene = [x(t), y(t), z(t)], stepwise = .1, linecolor = blue)

I did use stepwise and {ic} as posted above.  Did I miss something?

> dePlot := DEplot3d(sys, [x(t), y(t), z(t)], t = 0 .. 10, {ic}, scene = [x(t), y(t), z(t)], stepwise = .1, linecolor = blue)

I appreciate that you pointed out the "post" and "question" difference since the new Maple Prime; In the old forum I used to "post a question".  

1.  I don't think the defining of sys is the problem.  the * is the result of of cut-and-paste.  I remove the blank (which may be taken as "*" the problem persists.

2.  ic1 and ic2, defines a list of intial values.  

> ic1 := [seq([.1*i, .5*i, 0], i = -5 .. 5)];

[[-0.5, -2.5, 0], [-0.4, -2.0, 0], [-0.3, -1.5, 0], [-0.2, -1.0, 0], 
  [-0.1, -0.5, 0], [0., 0., 0], [0.1, 0.5, 0], [0.2, 1.0, 0], [0.3, 1.5, 0], 
  [0.4, 2.0, 0], [0.5, 2.5, 0]]

> ic2 := [seq([0, -.3*i, .5*i], i = -5 .. 5)];    

 [[0, 1.5, -2.5], [0, 1.2, -2.0], [0, 0.9, -1.5], [0, 0.6, -1.0], 
        [0, 0.3, -0.5], [0, -0., 0.], [0, -0.3, 0.5], [0, -0.6, 1.0], 
        [0, -0.9, 1.5], [0, -1.2, 2.0], [0, -1.5, 2.5]]

I have used initial conditions defined in such fashion and it works jut fine for DEPlot.  It ivery possible that you're right about the syntax for Initial conditions defined for DEPot3d.  It seems to suggest what you mentioned.  I have used the following initial condition and it does NOT work either

> ic := [[x(0) = 0, y(0) = 0, z(0) = -2.5], [x(0) = 0, y(0) = 0, z(0) = -2.0], [x(0) = 0, y(0) = 0, z(0) = -1.5], [x(0) = 0, y(0) = 0, z(0) = -1.0], [x(0) = 0, y(0) = 0, z(0) = -.5], [x(0) = 0, y(0) = 0, z(0) = 0.], [x(0) = 0, y(0) = 0, z(0) = .5], [x(0) = 0, y(0) = 0, z(0) = 1.0], [x(0) = 0, y(0) = 0, z(0) = 1.5], [x(0) = 0, y(0) = 0, z(0) = 2.0], [x(0) = 0, y(0) = 0, z(0) = 2.5]];  

[[x(0) = 0, y(0) = 0, z(0) = -2.5], [x(0) = 0, y(0) = 0, z(0) = -2.0], 
    [x(0) = 0, y(0) = 0, z(0) = -1.5], [x(0) = 0, y(0) = 0, z(0) = -1.0], 
    [x(0) = 0, y(0) = 0, z(0) = -0.5], [x(0) = 0, y(0) = 0, z(0) = 0.], 
    [x(0) = 0, y(0) = 0, z(0) = 0.5], [x(0) = 0, y(0) = 0, z(0) = 1.0], 
    [x(0) = 0, y(0) = 0, z(0) = 1.5], [x(0) = 0, y(0) = 0, z(0) = 2.0], 
    [x(0) = 0, y(0) = 0, z(0) = 2.5]]

> dePlot := DEplot3d(sys, [x(t), y(t), z(t)], t = 0 .. 10, {ic}, scene = [x(t), y(t), z(t)], stepwise = .1, linecolor = blue);

Error, (in DEtools/DEplot/CheckInitial) invalid initial conditions - must be list of lists of conditions

 deplot3d() gives me the following errors:

> dePlot := DEplot3d(sys, [x(t), y(t), z(t)], t = 0 .. 10, {ic}, scene = [x(t), y(t), z(t)], stepwise = .1, linecolor = blue);Error, (in DEtools/DEplot/CheckInitial) invalid initial conditions - must be list of lists of conditions

I appreciate that you pointed out the "post" and "question" difference since the new Maple Prime; In the old forum I used to "post a question".  

1.  I don't think the defining of sys is the problem.  the * is the result of of cut-and-paste.  I remove the blank (which may be taken as "*" the problem persists.

2.  ic1 and ic2, defines a list of intial values.  

> ic1 := [seq([.1*i, .5*i, 0], i = -5 .. 5)];

[[-0.5, -2.5, 0], [-0.4, -2.0, 0], [-0.3, -1.5, 0], [-0.2, -1.0, 0], 
  [-0.1, -0.5, 0], [0., 0., 0], [0.1, 0.5, 0], [0.2, 1.0, 0], [0.3, 1.5, 0], 
  [0.4, 2.0, 0], [0.5, 2.5, 0]]

> ic2 := [seq([0, -.3*i, .5*i], i = -5 .. 5)];    

 [[0, 1.5, -2.5], [0, 1.2, -2.0], [0, 0.9, -1.5], [0, 0.6, -1.0], 
        [0, 0.3, -0.5], [0, -0., 0.], [0, -0.3, 0.5], [0, -0.6, 1.0], 
        [0, -0.9, 1.5], [0, -1.2, 2.0], [0, -1.5, 2.5]]

I have used initial conditions defined in such fashion and it works jut fine for DEPlot.  It ivery possible that you're right about the syntax for Initial conditions defined for DEPot3d.  It seems to suggest what you mentioned.  I have used the following initial condition and it does NOT work either

> ic := [[x(0) = 0, y(0) = 0, z(0) = -2.5], [x(0) = 0, y(0) = 0, z(0) = -2.0], [x(0) = 0, y(0) = 0, z(0) = -1.5], [x(0) = 0, y(0) = 0, z(0) = -1.0], [x(0) = 0, y(0) = 0, z(0) = -.5], [x(0) = 0, y(0) = 0, z(0) = 0.], [x(0) = 0, y(0) = 0, z(0) = .5], [x(0) = 0, y(0) = 0, z(0) = 1.0], [x(0) = 0, y(0) = 0, z(0) = 1.5], [x(0) = 0, y(0) = 0, z(0) = 2.0], [x(0) = 0, y(0) = 0, z(0) = 2.5]];  

[[x(0) = 0, y(0) = 0, z(0) = -2.5], [x(0) = 0, y(0) = 0, z(0) = -2.0], 
    [x(0) = 0, y(0) = 0, z(0) = -1.5], [x(0) = 0, y(0) = 0, z(0) = -1.0], 
    [x(0) = 0, y(0) = 0, z(0) = -0.5], [x(0) = 0, y(0) = 0, z(0) = 0.], 
    [x(0) = 0, y(0) = 0, z(0) = 0.5], [x(0) = 0, y(0) = 0, z(0) = 1.0], 
    [x(0) = 0, y(0) = 0, z(0) = 1.5], [x(0) = 0, y(0) = 0, z(0) = 2.0], 
    [x(0) = 0, y(0) = 0, z(0) = 2.5]]

> dePlot := DEplot3d(sys, [x(t), y(t), z(t)], t = 0 .. 10, {ic}, scene = [x(t), y(t), z(t)], stepwise = .1, linecolor = blue);

Error, (in DEtools/DEplot/CheckInitial) invalid initial conditions - must be list of lists of conditions

 deplot3d() gives me the following errors:

> dePlot := DEplot3d(sys, [x(t), y(t), z(t)], t = 0 .. 10, {ic}, scene = [x(t), y(t), z(t)], stepwise = .1, linecolor = blue);Error, (in DEtools/DEplot/CheckInitial) invalid initial conditions - must be list of lists of conditions