loadrobot('robotiq2F85') - Missing joints or constraints

Hello,

I want to model the Robotiq gripper 2F-85 which is already in Matlab included.

I load the robot, set the position for a joint on the left finger and visualize it:

clear; clc; close all;

robot = loadrobot('robotiq2F85', 'DataFormat', 'row');
showdetails(robot);

--------------------
Robot: (10 bodies)

 Idx                     Body Name                          Joint Name                          Joint Type                     Parent Name(Idx)   Children Name(s)
 ---                     ---------                          ----------                          ----------                     ----------------   ----------------
   1            left_outer_knuckle                        finger_joint                            revolute           robotiq_arg2f_base_link(0)   left_outer_finger(2)  
   2             left_outer_finger             left_outer_finger_joint                               fixed                left_outer_knuckle(1)   left_inner_finger(3)  
   3             left_inner_finger             left_inner_finger_joint                            revolute                 left_outer_finger(2)   left_inner_finger_pad(4)  
   4         left_inner_finger_pad         left_inner_finger_pad_joint                               fixed                 left_inner_finger(3)   
   5            left_inner_knuckle            left_inner_knuckle_joint                            revolute           robotiq_arg2f_base_link(0)   
   6           right_inner_knuckle           right_inner_knuckle_joint                            revolute           robotiq_arg2f_base_link(0)   
   7           right_outer_knuckle           right_outer_knuckle_joint                            revolute           robotiq_arg2f_base_link(0)   right_outer_finger(8)  
   8            right_outer_finger            right_outer_finger_joint                               fixed               right_outer_knuckle(7)   right_inner_finger(9)  
   9            right_inner_finger            right_inner_finger_joint                            revolute                right_outer_finger(8)   right_inner_finger_pad(10)  
  10        right_inner_finger_pad        right_inner_finger_pad_joint                               fixed                right_inner_finger(9)   
--------------------

q = homeConfiguration(robot);
q(1) = 0.7;

f = figure;
f.Theme = "light";
show(robot, q, "PreservePlot", false, "Frames", "off");
view(90,0)
axis equal
axis tight

The problem is that the connection between the `left/right_inner_knuckle` and the `left/right_inner_finger` is missing as you can see in the figure.

Has anybody encountered this problem already - I guess I have to add some sort of constraint to the rigidBodyTree...

Thanks!

Homepage gripper: https://robotiq.com/products/adaptive-grippers

Datasheet gripper: https://blog.robotiq.com/hubfs/support-files/Product-sheet-2F-Adaptive-Gripper-EN-Tomahawk.pdf