The issue is related to an ERPNext fixture issue https://github.com/frappe/frappe/issues/18516. Uninstalling pibiCal will not remove custom fields nor client scripts from ERPNext desk.
The remaining custom field Event-minute on the Event Doctype will break ERPNext calendar and all other doctypes that have calendars.
Use Administrator account to remove this field and disable pibiCal scripts.
The issue is related to an ERPNext fixture issue https://github.com/frappe/frappe/issues/18516. Uninstalling pibiCal will not remove custom fields nor client scripts from ERPNext desk.
The remaining custom field Event-minute on the Event Doctype will break ERPNext calendar and all other doctypes that have calendars.
Use Administrator account to remove this field and disable pibiCal scripts.