There is a definite link between the ABS light and transmission failure. When the ABS light is on , the torque converter unlocks. An unintended consequence was the fluid got much hotter and it overwhelms the trans cooler.
I've looked at the circuit on a wiring diagram and found the one wire to cut to prevent the TCM from seeing ABS light input. So now if the ABS light comes on, it's not going to risk damaging the transmission
Hino fixed this in 2017, I think. Possibly 2015.
Have you had it re-scanned since this new problem developed? When they replaced the trans, they're supposed to reset the shift adaptions in the TCM. Do you know if this was done? The TCM has learned the characteristics of the old transmission, so if you stick a new trans in and don't reset it, that can cause issues.
They likely wanted to replace the radiator because when a trans grenades the shrapnel ends up in the trans cooler. You can destroy a new transmission when debris makes it through the cooler.