How could Abijam and Asa both have the same mother if Asa was Abijam's son?

Question

As the title. In Melachim chapter 15 it goes through the kings of Judah and it speaks about how Abijam was king and then he dies and his son Asa takes over but twice it says "and his mother was Maacah daughter of Abishalom".

Am I missing something here?

Edit: So I read somewhere online that in this context it means grandmother.

Answer 1

Maacah the daughter of Avishalom is the grandmother of Asa, and the text call her his "mother" because the Scripture sometimes call a grandmother a mother (see Radak on Melachim I 15:10).

Answer 2

According to the version of Chapter 15 in the Septuagint the names of the mothers were not the same. Verse 2 reads:

καὶ τρία ἔτη ἐβασίλευσεν ἐπὶ ῾Ιερουσαλήμ, καὶ ὄνομα τῆς μητρὸς αὐτοῦ Μααχά, θυγάτηρ ᾿Αβεσσαλώμ

And he reigned three years over Jerusalem: and his mother’s name [was] Maacha, daughter of Abessalom.

Whereas Verse 10 reads:

καὶ τεσσαράκοντα καὶ ἓν ἔτος ἐβασίλευσεν ἐν ῾Ιερουσαλήμ, καὶ ὄνομα τῆς μητρὸς αὐτοῦ ᾿Ανὰ θυγάτηρ ᾿Αβεσσαλώμ.

And he reigned forty-one years in Jerusalem: and his mother’s name [was] Ana, daughter of Abessalom.

Notably, though, in II Chronicles (11:20 and 15:16) the Septuagint does have the same name for both mothers.