Trigger view names are available in Target notification calls on the page, but they are not available within Target VEC while creating the activity. Why?
To troubleshoot such scenarios
Ensure that trigger view function (custom code) is fired after ‘Fire Page Load Request’ action in Target rule
Visit the webpage and ensure that trigger view is available in notification call each time on the activity URL, while navigating through the page.
VEChelper extension might be inserting the library which will not load trigger view, so disable the extension to verify
SameSiteattribute might be affecting the pageload in VEC when using Chrome, resulting into issue. Use other browser like Mozilla to avoid this scenario.