i also have an indica (endless sky) that did that from seed.
I second this, Bog's genetics often give twins...pretty cool!bog seeds are notorius for twins . i got 2 twins from a ten pack sour b. yours aint a twin just self topped and yes i have seen that several times
once or twice, It usually performs as well as the others
i call it self topping plant, not twin .i have seen it several times .