Septuagint
And he offered a sacrifice in the mountain, and called his brethren, and they ate and drank, and slept in the mountain
καὶ ἔθυσεν Ιακωβ θυσίαν ἐν τῷ ὄρει καὶ ἐκάλεσεν τοὺς ἀδελφοὺς αὐτοῦ καὶ ἔφαγον καὶ ἔπιον καὶ ἐκοιμήθησαν ἐν τῷ ὄρει
MT
And Jacob offered sacrifice upon the mount, and called his brethren to eat bread: and they did eat bread, and tarried all night in the mount (KJV)
ויזבח יעקב זבח בהר ויקרא לאחיו לאכל־לחם ויאכלו לחם וילינו בהר
This verse is different between the MT and Septuagint, the MT repeats the word לחם 'bread. The Septuagint does not mention bread, just says they were eating and drinking.
This is what the Septuagint is reading.
ויזבח יעקב זבח בהר ויקרא לאחיו ויאכלו וישתו וילינו בהר
1. Was Jacob "In", "On" or "Upon" the mountain?
2. What did Jacob sacrifice?
Comparison.
Gen 26:30
And he made them a feast, and they did eat and drink.
ויעש להם משתה ויאכלו וישתו
καὶ ἐποίησεν αὐτοῗς δοχήν καὶ ἔφαγον καὶ ἔπιον
καὶ ἐποίησεν αὐτοῗς δοχήν καὶ ἔφαγον καὶ ἔπιον
Homer, Odyssey Book 15 Line 373
they eat and drink
ἔφαγόν τʼ ἔπιόν
https://scaife.perseus.org/reader/urn:c ... BD&qk=form