HR - next leave period empty till January 1st 2021

This column has an ambiguous name.
It is not the next period of absence but the number of days acquired during the period.
We normally accumulate at the end of the month, according to the algorithm (which I remind you is not ours but an external contribution), it could even be from the 1st of the following month ...?

For the invalid control, it is not necessarily linked to this acquisition but just to the fact that this resource already has a negative balance and that the periods and duration of use do not allow it.

Once again, I encourage you to contact the contributor directly to exchange features that they have implemented.

I also remind you that he left a document available with the structure of the tables and a lot of information on how these rights are managed.