Anyone experiencing sporadic issues where some leads don't qualify for simple smart campaigns?

We have an event program active. Today, while looking at the registrants under the members tab, we noticed that 2 of the 9 people had registered (filled out the registration form on the registration page), but didn’t qualify for the smart campaign that would have changed their program status to “Registered”.  Instead, Marketo just used the first program status of this channel - which is normal, when a form is filled out within a program and no smart campaign is available for them to qualify. 

Looking at the activity log, it clearly shows that the form was filled out.  But Marketo did not capture the landing page where this form exists – which is what’s needed to qualify for the smart campaign.  Here's the smart list trigger:

Here’s the activity of a successful registrant:

And here’s a lead where Marketo didn't capture the registration page (notice the missing “Change Program Status”):

There is no rhyme or reason here.  It's happening completely random for different leads.  I've already raised a ticket with Support, but since they can't replicate it, they assume it's working properly now.