GA spike of users with not set landing page after install the script

[pec92]

Hi !
thanks for sharing this useful piece of code :)

I've tried to install the web vitals monitoring code using GTM. Data seems to be collected correctly, but then I noted a spike of user with location (not set) in GA data (see the screenshot below). After stopping the web vitals tag the data came back to normal. It's seems like a bot it's activated via this code, as you can see in the second screenshot the bad traffic is coming from USA with Linux OS and null session duration. Can you help me with this issue please? Do you know another cdn for getting the code?

spike data

details

Many thanks,
Daniela

[philipwalton]

Hmmm, I'm not sure why that would be. What is the hostname for the pageviews in that session?

In my experience bots and spammers send data containing URLs with an incorrect hostname, and so setting a filter on your view to only accepts hits with a hostname that matches your domain has generally worked for me to avoid all spam.

[pec92]

Hi Philip !

thanks for your hint.

I've added the hostname as secondary dimension for all not set landings, but it seems that all the traffic is coming from the correct website hostname, so I cannot filter it out.
It's really weird because (not set) landing were registered only when we had the web vitals tag active, and stopped just after we stopped the tag.

Thanks,
Daniela

[robflaherty]

Did you see a drop in pageviews too? Looks like pageviews may not be firing which would explain the not set landing page and the low number of sessions.

[psabharwal123]

this happens when event is the first interaction on a page, we fixed it by making sure that web vital events always fire after the first page view.

[philipwalton]

I'm going to close this as I suspect the issue is with this specific property's implementation and not an issue with the web-vitals library or its usage instructions related to GA. Please reply here if you discover otherwise.

[smhmic]

The reason for this is because CLS can send multiple times per pageload and LCP will send when the tab unloads. If sending these values to GA as a non-interactive hit (which you should) then these hits will not extend the GA session. And if no subsequent pageview fires, then these hits will cause Landing Page = (not set).

So basically this will happen whenever:

• the user has the page open longer than the GA session timeout (30 min by default) w/o triggering other tracked events
• the user opens the page shortly before midnight based on the timezone you have set the GA view settings

I just submitted a new request which may help address this.