Tracking # Website Visits
Hi Marketo Community,
I'm trying to track # times a lead visits a website by creating a smart campaign that triggers the following whenever someone Visits Web Page = Any.
Using a custom integer field "# Website Visits", I set my flow to trigger a #1 each time a person visits our website (can pass through every 1 day).

Initially when I set the Default choice of "+1" the red squiggly lines show up indicating this is not an accepted integer. However, sometimes that squiggly line disappears, and I'm still able to activate the campaign. The problem is that after I activate the campaign and return to my flow, the Default New Value "+1" disappears, essentially changing the default back to "do nothing."

Can someone help me understand why I can use the "-1" but not the "+1" for this field? I'm able to use both "+" and "-" data field updates without a problem when it comes to the Person Score or Behavior Score fields, so why doesn't this work with a custom field?
Appreciate any insight I can get.