find_scheduled_day_slot returns 500 error for specific months

[Valentina R]

Reported here:

we have an issue with calendar – it not loading only at november 2022 (if we move forward from july to october – all fine

but at november we have Internal server error.

Server admin says that plugin creating big load on server and not db requests not optimized.

Probably connected with this issue.

[Valentina R]

it was related to custom rules