Activity URL is changing to another URL itself in page delivery after saving the activity

We have created an AB test activity using a URL let's say - https://www.domain.com/category/abc. Now when we go to the page delivery settings, we see https://www.domain.com/ as the activity URL instead of the actual activity URL. There is no redirect applied to the activity URL. We tested two different scenarios as well.

Scenario 1: We made the modification using custom code (refer the image below). After saving the activity:

• The activity URL changed to the homepage URL in page delivery settings.
• In VEC, instead of the activity URL page, the homepage loads.

Scenario 2: Using VEC features, changed the h1 heading. No custom code used. After saving the activity:

• The activity URL changed to the homepage URL in page delivery settings.
• In VEC, activity URL page loads every time you click on the Edit Activity.

Although, in both the scenarios, we could see the desired experience, but we want to understand why the Activity URL is changing itself in page delivery settings. Is this a bug?