Apologies for this being somewhat vague but we have not been able to pinpoint the reason for this very strange issue. The issue is that when a user first lands on our website everything is loading as expected, but after navigating to any other page on the site (the second page view), the majority of our page load rules do not fire. (Note: this is NOT a single page app, so page load is the correct trigger). Also to note, as soon as you navigate a second time and onward (3rd page view+) everything works fine again.
I will be happy to share more specific information on the 3rd party tags that are associated with this issue, but I just wanted to throw this out there to see if anyone has experienced this before.