Hello,
We asked you the confirmation that the "free product" stays in the cart while the coupon was removed.
That's was just the confirmation we needed in order to know in which direction we needed to go for the investigation.
I wrote the same thing few days ago
To be sure, just remove the product from the "discount free product" and set a "1 EUR" fixed discount instead.
If you do have the same issue, then it's coming from the coupon configuration or HikaShop ; otherwise it's from the plugin.
Please understand that if you do not provide the information regarding that point, we can't go forward.
Autoloads coupons are tricky and the algorithm is a complex one ; detecting modification of autoloaded coupons are difficult too because they can avoid triggers while removing a coupon, forcing the "coupon free product" to perform extra tests.
The current issue is related to the way that the autoloaded coupon was removed, since there was no more trace in the cart object.
The coupon can be "empty" but the entry can be removed from the object, telling the system that we don't want to touch that value ; it allows to update only partial information in the database.
Since the "coupon free product" was expecting an empty value when a coupon is removed and that was an autoloaded one is removed the coupon entry is also removed (not just empty), the detection of the removal was not working anymore.
Thus we had to find another way to detect that even in the plugin to make it work even with autoloaded coupons.
You can redownload the coupon free product plugin to get the patch.
And the next time you have issue, please provide the details to help the team understand the nature of the problem.
Regards,