Range ends highlighted in all months for multi month view

Describe the bug

When using range selection in multiple month view, the range end dates are getting highlighted in all months when range is spanning more than one month.
Range selection form 1-Jan-2025 to 10-Mar-2025 is highlighting dates 1 and 10 in all months with selection.

Pull Request Link

No response

Reason for not contributing a PR

• Lack of time
• Unsure how to implement the fix/feature
• Difficulty understanding the codebase
• Other

Other Reason

No response

Reproducer

https://stackblitz.com/edit/primeng-multimonth-range?file=src%2Fapp%2Fapp.component.html

Environment

Reproducible in any browser with PrimeNg 18.

Angular version

18.0.1

PrimeNG version

v18 (LTS Only)

Node version

No response

Browser(s)

No response

Steps to reproduce the behavior

1. Navigate to stackblitz link attached above.
2. Pre selected date range is from 1-Jan-2025 to 10-Mar-2025. The calendar view will by default show only the last selected month (March). Move back 2 months to see selection form Jan and Feb.
3. Check the start and end highlight of the selection range.

Expected behavior

Only 01-Jan-2025 and 10-Mar-2025 should be highlighted

Start with the StackBlitz reproducer and its src/app/app.component.html entry point, using the preselected range from 1-Jan-2025 to 10-Mar-2025 in the multi-month calendar. Check the January and February views after moving back two months. Done means only 01-Jan-2025 and 10-Mar-2025 are highlighted, while intermediate-month dates are not.