So apparently a new mechanic for Terastalize was discovered; if a move of your Tera type has less than 60 BP, its BP gets raised to 60 while Terastalized, except for priority moves, multi-hit moves, and the following moves:

>Crush Grip
>Dragon Energy
>Electro Ball
>Eruption
>Flail
>Fling
>Grass Knot
>Gyro Ball
>Heat Crash
>Heavy Slam
>Low Kick
>Reversal
>Water Spout