Thanks for the information, that was helpful. From the snap-shot of your model, it seems you are using R2019b (please verify using "ver" command in MATLAB).
Verify the names of the buses in your base-workspace.
The service request bus name (if it followed the convention of model name appended by request message name) would have been longer than 63 character limit.
So, generated bus name is truncated to meet the 63 character limit and unique hash string is appended to it.
It's recommended to use the data-type drop-down in MATLAB function editor to select the correct Simulink bus data-type.