I have also tested different browsers with/without incognito.
Without ?test=123 the icons remain the same, with ?test=123 icons are changing.
Anyways, I can only recommend to check the causes which were already identified in the past at other users. In your case I would recommend checking and/or changing the CF7 language settings. In addition you can try to create a new dummy form and check if the translation is working there.
I hope this is the cause in your case and you can fix it.
Source: https://www.ads-software.com/plugins/contact-form-7-image-captcha/#language%20issues%3F
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3 Contact Form 7 language settings
Contact Form 7 saves a meta variable for the language of each respective form and this is being done when you FIRST save the form.
In this case, you have the following options:
- Change the variable via the WordPress database directly (look for the post ID of the respective form in the postmeta table and there’ll be a “_locale” option).
- Make sure to change the language in your WordPress backend to your desired target language and then simply re-create the CF7 form.
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