Specific days frequency should be added when a calendar assigned includes the same date

Current situation

• On adding the frequency for Specific days when the selected date is already added by the calendar then the frequency is not added.

How to Reproduce

• Assign a calendar to job/order with a period. For example Calendar with a frequency of every day and validity dates from 1st May to 31st Aug.
• Add the specific day frequencies to the job/order with a date that is already added by calendar (example: From 1st May, 19th May, 29th June, etc).
• The specific day frequency will not be added.

Desired behavior

• The specific day frequency should be added even the date is already covered by the calendar.