Importing an array from workspace into Simulink, but Simulink can't access the last element in that array

I'm trying to build a model in Simulink right now that uses a custom Matlab function to read in an array containing input data and create a step function. The input array is always a 1x8. Only problem is, when my function tries to call the eighth element in the array, the simulation stops and throws this error:

    Index expression out of bounds. Attempted to access element 8. The valid range is 1-7.

What is going on here? Why does it seem like the vector is being concatenated in the import stage? How can I fix this?

EDIT: I have tried using a Signal Specification block set to 8 and using Edit Data/Ports to set the input size for that vector to 8 from -1, neither solution worked, however.

[Liang Ma]

I have the same issue.

Did you resolve it?

If not, this is like a bug of simulink. I would like to call for tech support from mathworks.