As an end user you need to understand that you have to mouseover the calendar, to find out that you’re watching it via pages, and in combination with the global setting Don’t notify space or page watchers, you won’t get the notifications for events in the calendar.

In a user friendly scenario, the tooltip would state that the global setting is enabled, and you won’t get notification along with a link to how to remedy (stop watching page, and directly watch the calendar)

Another approach would be to even though you’re watching it via a page, have the option to watch the calendar to get notifications.

Workaround 

Below customization was suggested to the user for the time being. Here are the steps to achieve it:

• Go to Confluence administration > Layouts
• Under Site Layouts, Click on Create Custom next to Main Layout
• The Decorator Content will open, which has the code for the Main Layout.
• The added disclaimer should be before the $body
• Search for this string $!sitemeshPage.getProperty("page.tab-navigation")
• Paste the below code above it and save.

  ## Add a disclaimer for the Team Calendar page
      #if ($req.getRequestURI().contains("calendar/mycalendar.action"))
          <div class="disclaimer" style="background-color: #f8f9fa; border: 1px solid #ccc; padding: 10px; margin-bottom: 15px;">
              <strong>Important Notification Information:</strong>
              <p>If you see the <strong>"Watching"</strong> option enabled for a calendar, please note that notifications for calendar events depend on the global setting: <strong>"Don't notify space or page watchers"</strong>, found under <strong>Confluence Administration - Team Calendar</strong>.</p>
              <ul>
                  <li><strong>What This Means:</strong>
                      <ul>
                          <li>You may appear to be "watching" the calendar because you're watching its associated space or page.</li>
                          <li><strong>You will not receive notifications for calendar events</strong> unless you're directly watching the calendar.</li>
                      </ul>
                  </li>
                  <li><strong>To Receive Notifications for Calendar Events:</strong>
                      <ol>
                          <li>Mouse over the calendar to check if you're watching it via a page.</li>
                          <li>If so, stop watching the page or space.</li>
                          <li>Directly watch the calendar by clicking the <strong>Watch</strong> button on the calendar.</li>
                      </ol>
                  </li>
              </ul>
              <p>For more details, refer to the <a href="https://confluence.atlassian.com/doc/watch-a-calendar-1044780432.html">documentation on Team Calendar notifications</a>.</p>
          </div>
      #end