If you notice that not all products in your collection are being discounted and have not seen it fixed by restarting the discount, consider trying this alternative approach. We created this workaround after a one time Shopify bug that occurred in August 2024 where collections were not being sent to us properly, but this solution may prove useful if something similar happens again.
First we need to visit the Products page in your Shopify admin and do the following:
Firstly please ensure that the discount you have which currently targets the collection is disabled. From here, you can either edit that discount to target the tag you added in the steps above or create a new discount to do the same.
To target a tag, simply change the 'Discount Targeting' to 'Specific Tags' and enter the tag you just added.
That is it! If you need any help, then please contact support and we will get back to you as soon as we can.