As requested, I’ve recorded a video demonstrating the issue. In the first half of the video, you'll see that on one site (with the same version), the product section does not have the "+" button to add values. In the second half, on another site with the same version, the "+" button is visible and working.

please take a note, each option have a it's own type.
Selectbox is a multivalue. Label - not.

yes sure!

I hope you're all doing well.

I'm reaching out to seek guidance regarding an inconsistency I've encountered in the product editing interface after upgrading two different sites to version 1.4.2.

Issue Description:
On Site A (upgraded to v1.4.2), when I navigate to:

Products → Edit Product → Options Tab

I can see a plus (+) icon located above the Save button. This icon allows me to conveniently add more option values for that product.

However, on Site B, which has also been upgraded to the same version 1.4.2 and follows a very similar configuration:

Products → Edit Product → Options Tab

I do not see the plus (+) icon for adding more option values in the same location.

Thank you in advance for your support!

Yes, I've already done it and nothing. Here's an image showing that everything is fine. I still don't understand why it doesn't change, and I've already checked and can't find the solution.

What file do I have to open to get the HTML code you're showing me? Thank you.

you can open any page

No, we do not have any issues with jpg or png files. It seems the hosting site IT team made some changes that seem to help considerably. Here below is there response:
"We’ve reviewed the issue reported on your website and found that it was likely related to PHP’s memory limit settings not properly reflecting on the site.

To address this, we have created a .user.ini file within the root directory of your site and increased the PHP memory_limit to 2048M (2GB). This change ensures that your application has access to more memory, which can help prevent memory-related errors during operation.

At this time, no further errors are appearing in the logs, but we recommend that you test the site and let us know if you experience the same issue again. We appreciate the productive communication with the AbanteCart IT team during this process."