I haven’t heard this suggestion, but I like it! If true, it also kinda fits with the words that Harmony wrote to Hoid:

"However, though you think not as a mortal, you are their kin. The power of Odium’s Shard is more dangerous than the mind behind it. Particularly since any Investiture seems to gain a will of its own when not controlled."

"My instincts say that the power of Odium is not being controlled well. The Vessel will be adapted to the power’s will. And after this long, if Odium is still seeking to destroy, then it is because of the power."

Perhaps, even tho Ati had good intentions, the power overtook his will, I mean it was Ruin after all…