1424797 - Predictive prefetch makes duplicate HTTP requests still causing duplicate ad impressions

Status: UNCONFIRMED

(DevTools :: Netmonitor, defect, P5)

Description

[Anara]

Attachment: duplicated_ad_impressions.png

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36

Steps to reproduce:

1. Go to https://www.appliancesonline.com.au/indesit-xwa71283waus-7kg-front-load-washing-machine/ 2. Scroll to the bottom of the page, You may also like section 3. Open network tab, check persist logs, filter by sp. (snowplow tracking calls) 4.Click on any product in you may also like section. 5. Observe snowplow network calls, there will be impression click duplicates. Screenshot attached. First and third call are duplicates. Call starts before page load and duplicates itself when new page is loaded.


Actual results:

I look after implementation of tracking on our website and our QA team raised an issue that there are duplicate tracking GET calls/ad impressions. I went to DB to confirm this and indeed noticed duplicate tracking GET calls/ad impressions.

Scenario is : click on product tile on one of our pages and look at network calls, there should be only one impression tracking call onclick. But there are two identical ones.


Expected results:

Only one network call/ ad impression.

Comment 1

[Anara]

Sorry, forgot to mention, I am on Firefox 57.0.1 on MacOs Sierra. Found similar issue for Firefox 52.0 https://www.fxsitecompat.com/en-CA/docs/2017/predictive-prefetch-makes-duplicate-http-requests-in-iframes-causing-false-ad-impressions/

Comment 2

[Jan Honza Odvarko [:Honza] (always need-info? me)]

How do you know they are duplicates?
I can see more i?stm requests, but if selecting them and checking the Params side bar they have different query string

Also, can you please recheck with Firefox 61?
https://www.mozilla.org/en-US/firefox/channel/desktop/#nightly


Honza

Comment 3

[Anara]

(In reply to Jan Honza Odvarko [:Honza] from comment #2)
> How do you know they are duplicates?
> I can see more i?stm requests, but if selecting them and checking the Params
> side bar they have different query string
> 
> Also, can you please recheck with Firefox 61?
> https://www.mozilla.org/en-US/firefox/channel/desktop/#nightly
> 
> 
> Honza

Just updated to Firefox 60 on Mac High Sierra and still seeing duplicates. 

I check if it is a duplicate by base64 decoding onf cx and ue_px fields in params section in network tab. Also you can compare request URL, it is the same. 

They both have cx : 

{"schema":"iglu:com.snowplowanalytics.snowplow/contexts/jsonschema/1-0-0","data":[{"schema":"iglu:com.google.analytics.enhanced-ecommerce/impressionFieldObject/jsonschema/1-0-0","data":{"id":"WMY7046LB2","name":"Beko WMY7046LB2 7kg Front Load Washing Machine","list":"product-recommendations","brand":"Beko","category":"","variant":"product","position":1,"price":562,"currency":"001"}}]}

and ue_px : 

{"schema":"iglu:com.snowplowanalytics.snowplow/unstruct_event/jsonschema/1-0-0","data":{"schema":"iglu:com.google.analytics.enhanced-ecommerce/action/jsonschema/1-0-0","data":{"action":"detail"}}}

Comment 4

[Anara]

sorry request URL is slightly different, it has different stm value, but the rest is the same. If you compare to Chrome, there is only once network call.