In reverse order: yes, they are missing an X - the Arabic numerals at the very top right state that this is the page for 1826/27 (which is true for the top two-thirds of the page, the bottom also adds in 1828).
Transcription of the bride's entry: "Susanna Gündertin des selig. Paul Gündert gews Mittnachb u. Fleischhauermeister in Rükelsdorf u. s. Ehegl. Susanna g. Steltzerin jetzt mit Elias Gündert verehligt d. ehl. ältere Tochter"
Translating this highly abbreviated entry: Susanna Gündertin, legitimate older daughter of the late Paul Gündert, formerly member of the village community and master butcher, and his wife Susanna nee Steltzer, who is now married to Elias Gündert".
So yes, you are correct, Susanna Steltzer was indeed married to two different Günderts.