[Amazon] A product can not be added to the "Product list" after calculating the trade-in saving

[Softvision-RemusDranca]

[Affected versions]:

• Firefox Release 64.0 and above

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• Have a new Firefox profile with the latest version of "Price Wise" (18.0.0, date: 01.08.2019) installed.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites and navigate to "https://www.amazon.com/".
2. Open a product page from "Trending in video games" section (ex: product).
3. Wait until the "Trade-in" savings are calculated and click the "Price Wise" toolbar button.
4. Click the "Add This Product" button and observe the behavior.

[Expected result]:

• The product is added to the "Product list".

[Actual result]:

• The "Add This Product" button is inactive and the product cannot be added to the "Product list".

[Notes]:

• This issue is also reproducible on "AmazonSmile" website.
• However it seems that the product can be added while the "Trade-in" savings are calculated. But the product is added with a wrong price on Windows. The decimal pointer is wrongly displayed on the price. Still, on Mac and Linux the price is correctly added.
• This issue is also reproducible with the TP version of "Price Wise" experiment.
• Attached is a screen recording of the issue:
  

[Osmose]

Thanks for the issue!

I can replicate this issue on MacOS. Probably something to do with the page semi-reloading during trade-in calculation?