It is my understanding that the end date is not required when preparing a budget. However, I see that whenever the end date is not defined, the budget only applies to the current period as shown in the pictures:
The end date is not defined: https://ibb.co/sKT6LG7
The category "groceries" 50dt/month, shows up in April but not in May:
On a different note, when a change applied to a budget, it only takes effect if we go to another menu then go back to "budgets"