We have been using Matomo and the WooCommerce Matomo plugin for a year without problems. We use user IDs in Matomo to identify our users. For the past couple weeks the WooCommerce plugin has been breaking the Matomo session so the order and receipt pageview are not connected to the user or their session. We also use the A/B Testing plugin, and this issue has rendered our tests useless as we can’t track conversions.
When looking at the requests sent to Matomo for normal browsing it is sending both a uid and _id parameter. The requests sent from the WooCommerce plugin do not have the uid parameter, but do have the _id parameter and the value is the same as the other requests from that user.
Should Matomo be recognizing that the _id is the same and tracking these together? Is there a setting to control this? Looking at the WooCommerce Matomo plugin, I don’t see any hooks I can use to set the user ID myself with those requests, and like I said this was all working fine until a couple weeks ago and I don’t know of anything that changed on our side that would have impacted this.