That’s an interesting one, is the error occurring for the one product only?
Do you also happen to be using a third-party app to control your discounts or products? If so, you can try to disable the app’s features if it’s available to do so within the app, to see if the issue will be fixed.
I see you’ve also tagged your post with the third-party theme tag — to rule out any third-party interference, I recommend troubleshooting further by installing a fresh copy of a Shopify theme. You can do this by going to Online store > Themes > Explore free themes, and select a theme to add to your library. From there, click on Actions > Preview, and you can then view the discount amount on that product to see if it’ll now function properly.
If the issues don’t persist on the fresh theme, chances are a third-party code on your store may be interfering with the discount feature on your store. If you or a developer working on your store have made any code changes recently to your theme, the newly added code may also be the cause of this issue.
If you need further help to look into this situation, you can contact our team so that we can take a closer look at your account from our end. We aren’t able to do this via the Community Forums at this stage, due to security reasons, but you can reach out to our support team via our Help Center here. Once logged in on the Help Center, select a topic that best fits your query or situation. From there, you’ll be taken to a page with a list of relevant support articles, and you can scroll to the bottom of that page to select your preferred contact method with our team.
Once your discount is live on your store, make sure to also keep an eye out on your discount analytics. This will allow you to understand which discount strategies have worked, and will help you tailor a strategy that works best for your business moving forward.
I asked the development team of my theme. And they reply with this:
The error is connected with mathematical calculation of the discount percent.
The error appears on prices when normal price and price to compare have not the same symbols.
For example, one price has a comma and a dot, but the main price has a comma only and no dots.
So, you should make the same prices configuration.
Then I tested it and found this true, see here:
I tested the error and found that if you have a compare price above 999, then shopify will write it as this 1.110,00 and if you set the price under 1.000, like 990,00, then the error will happen.
So price 990,00 and compare price 1.110,00 then the error happens because of the thousand dot, as pointed out.
So do you maybe know how to stop shopify writting the thousand dot or the comma zero zero after a price?