PHP strings detected by WordPress but not by Loco Translate

Hello, Tim.

I developed this WordPress plugin, and as you can see, its strings are automatically detected by www.ads-software.com:
https://translate.www.ads-software.com/locale/sah/default/wp-plugins/featured-image-from-url/

However, a user reported that Loco Translate isn’t detecting them, and I was able to reproduce the issue. The plugin strings are located in admin/strings.php.

I have already increased this option:

• Skip PHP files larger than: 200K

And this option seems fine:

• Scan PHP files with extensions: php, twig

But still no luck. Am I missing something?

Thank you for your help.