Este reporte es para Adolfo Jayme Barrientos.
Este error podría ser resuelto en las próximas versiones de L.O Calc 6.1.2 y LO Calc 6.0.7, en Español, ya que el mismo se reproduce en la versión 6.0.6 en Español.

Adolfo: if you need someone to change something on Pootle, don't hesitate!

CORRECCIÓN
No es en LO Calc sino en LO Impress donde existe este error. Me disculpo por la equivocación.
Este error podría ser resuelto en las próximas versiones de L.O Impress 6.1.2 y LO Impress 6.0.7, en Español, ya que el mismo se reproduce en la versión 6.0.6 en Español.

This error appears when I use the new User Interface with Tabs - (Experimental) - which is activated (in Libreoffice Calc) like this:
Go to View - User Interface - Tabbed.
This error persists in LO Impress 6.1.1. and LO Impress 6.0.6 - Spanish version.

Para evitar confusiones, yo solicito eliminar el Comentario 1 hecho por mí.

I want to correct the path where the error appears:

1. Open LibreOffice Impress 6.1.1, and 6.0.6, Spanish version.
2. Go to the "Insert" Menu. In Spanish: "Insertar".
3. Look for the "Slide Number" option. There is the error. That option appears in English, but it should appear in Spanish because I am reporting this error for LO Impress in Spanish.

This issue is also covered in bug 119948.
Let's close this as a dupe of bug 119948

*** This bug has been marked as a duplicate of bug 119948 ***

These translation errors also appear now in LO Impress 6.1.3, Spanish version. "Slide Title" and "Slide Count" options appear in English. The translation of these options into the Spanish language was not carried out. The correction was not made in LO Impress 6.1.3.

I am testing LO Impress 6.2 and LO Draw 6.2, in Spanish, activating the new User Interface with tabs, and again I have found those translation errors in the Spanish version, in the same 3 options of the branch that emerges from the Icon "Field", under the "Insertar" tab. This error is still too evident in IMPRESS and in DRAW 6.2 where the options "Slide Number", "Slide Title" and "Slide Count" have yet to be translated into Spanish. The same thing happens in the following route in both LO Impress 6.2 and LO Draw 6.2: Menu "Insertar"> "Campo". There is also the error. I see those options: "Slide Number", "Slide Title" and "Slide Count" in English, without being translated into Spanish as it should be because it is a Spanish version. In other words, this translation problem is still not resolved in version LO 6.2, in Spanish, or in LO 6.1.5 in Spanish. This directly affects users who are not bilingual, whose native language is Spanish.