Ecommerce tracking: "Trying to access array offset on value of type null"

The following message appears on my MultiSites home page (/index.php?module=MultiSites&action=index&idSite=1&period=range&date=previous7) since a few days, when I’ve updated to Matomo 3.13.1 and started logging ecommerce metrics.

WARNING: /var/www/html/plugins/Live/Visualizations/VisitorLog.php(225): Notice - Trying to access array offset on value of type null - Matomo 3.13.1 - Please report this message in the Matomo forums: (please do a search first as it might have been reported already) (Module: Ecommerce, Action: getEcommerceLog, In CLI mode: false)

I’m using Matomo 3.13.1 official docker image with two plugins MarketingCampaignsReportingPlugin and EnvironmentVariables. Here is my Dockerfile.

The message appears 8 times, which does not match the number of sites I have (11):

If I reload the page, the message disappears. But it comes back after a while.

My ecommerce tracking code looks like this:

    308871, // (required) SKU: Product unique identifier
    'Un an (5 numéros) - France métropolitaine', // (optional) Product name
    null, // (optional) Product category.
    50, // (recommended) Product price
    1, // (optional, default to 1) Product quantity

    53781, // (required) Unique Order ID
    50, // (required) Order Revenue grand total (includes tax, shipping, and subtracted discount)
    50, // (optional) Order sub total (excludes shipping)
    0, // (optional) Tax amount
    0, // (optional) Shipping amount
    // false // (optional) Discount offered (set to false for unspecified parameter)

Is this because I’m logging null as a product category? If so, how can I log product price and quantity while ignoring product category?


I’m getting the same issue on all three installs that we have running :frowning: