This has been created after applying an immediate fix @
Basically it's about how numerical (int, float...) parameters are handled by calendar API and, by extension, globally. More specifically when the numerical values have leading zeros.
There are various approaches to solve / improve current situation, and they are NOT mutually exclusive.
A) Modify the calendar API internals to better support passed params with leading zeros. Cast within the functions body.
B) Modify the calendar API applying for more type-hinted params that will perform the correct implicit casting.