New RTT right period creation inconsistent

Hello,

once I fixed the problem submitted on the following subject  [SOLVED] Leave right doubled after changing year
I realised, my RTT configuration wasn't correct, so I took the pdf documentation and I changed the settings on the CDI Contrat Type.
 
People must be able to use their RTT from 2020 until 31/01/2021

In order to do this, I had to change all the contracts to a default contract (that has no leave rights), to modify the settings of the CDI contract and then reaffect CDI Contract to all the employees.

But at that moment, some employees got 1 RTT right on the period of 2021 and some other got 0. Can you give me an explanation for this difference, please?
  
Thank you for you help.

Regards,
MCanuto