Suspend data problem

Dear Sir or Madam,
I am a software developer working for the TheSpian agency and  we have been tasked to make an e-learning platform from scratch( Ruby on Rails as backend and ReactJS as frontend). Currently, our client has more than 1000 courses on Articulate 360.

I have made a small testing concept, first I generated a sample course on Storyline 360, exported it as xAPI type, and uploaded it to the Amazon S3 server. I have set up a scaffold Rails application that acts as an LMS and LRS. I have managed to show and play the course within an iframe inside my LMS. The problem is with GET requests on my LMS server once the course has been initialized. Initial GET requests consists of 3 requests, stateId=cumulative_time, stateId=bookmark and stateId=suspend_data. Cumulative time and bookmark are loaded successful but I have got a problem with suspend_data when I receive GET request I give back JSON format with something like this: {"v":2,"d":[123,34,112,114,111,103,114,101,115,115,34,58,256,108,263,115,111,110,265,....],"cpv":"xe0ZAbYL"} and process which user already has been completed doesn't load up, but cumulative time and bookmark does.
Please can you help me, I have been stuck on this for a few days, and I couldn't find any corresponding information online...
Thank you in advance!