Why does Medea and Achilles get married in the afterlife like this has to be the most Random Ass pairing to ever exist?

I know right? It's so strange. Medea and Achilles aren't even (or at least shouldn't be) contemporaries, so I also wonder why they were paired up. Achilles and Iphigenia make sense based on their pretended marriage that led to her death, Achilles and Helen also make some sense because several connections exist between them and it is even claimed in the Catalogue of Women that he would have been the one to win her hand if he had been old enough to compete for it, but Achilles and Medea? It is kind of mind-boggling.

To make things even weirder, apparently Medea's husband had an erotic interest in Achilles' mother according to an account attested by Plutarch in „On the Malice of Herodotus”: „… that temple of Aphrodite which is said to have been founded by Medea, when she desired, as some affirm, to be delivered from loving her husband Jason, or, as others say, that the goddess free him from loving Thetis.”

Ettore Cingano, in „The Power and Failures of Thetis in Early Poetic Traditions and Beyond” suggests the following as possible reasons for the association of Medea with Achilles:

„My tentative guess is that the association of Achilles with Medea, connecting the Argonautic myth to the Trojan myth, originated from a combination of these elements, which included the wedding of a goddess and of a sorceress descending from Helios to two mortal heroes, the shared motherhood experience of Medea and Thetis, marked by the vain search for immortality for their children, Hera's personal bond with both women, the geographical proximity or identity of the adventures and life of Peleus and Jason, but also a further parallelism between Jason, Medea's first husband and Achilles, her husband in the afterlife, both of whom were reared by the centaur Chiron as was also the case with Peleus.”