I have no idea what it could be. Sounds to me like Unity doesn't like the meshes being destroyed - thats the only thing different tk2dSprites do. Try GLES3.0 if you're on 2.0, and also the opposite, I've seen Unity do some weird things running on some android devices (eg. try running anything nontrivial (just normal models, no tk2d) in GLES3.0 on Note4 = crash)
This can't be a 2D Toolkit bug if it only crashes on one piece of hardware, its a Unity / GL driver issue - if you can reproduce it 100%, send them a repro case.