Search form changing without apparent reason

Hi,

The GD Search Form in the Home page of my site https://inforoses.com changes depending of browser and language (WPML with four languages: Catalan Main language and Spanish, French and English secondary languages) is shown in desktops in two different shapes (good and bad).

Strings within the form have been translated with WPML String Translation.

I am enclosing two attachments showing the form in good and bad shape.

What happens is the following:

1) In Chrome the form is usually shown in good shape in the four languages, but sometimes only in catalan, the main language.

2) In Edge the form is shown in bad shape in all languages except the main one, catalan but sometimes it is shown in good shape in all languages.

3) In Explorer the form is shown in bad shape in all languages.

4) In Firefox the form is shown in bad shape in all languages, but not always.

5) In Opera the form is shown in bad shape in all languages, but not always.

6) In Maxthon, the form is shown in bad shape in all languages.

What could I do to have the form shown in desktop in good shape always in any browser and in any language?

I look forward to your reply.

Thank you very much once again for your help.

Best regards.