internal verification failure {invalid index in indexed group}

i got the same thing, did u ever fix it?

Change your expressions from Java Script to Legacy. For Motion Bro, this started happening in AE 17, but changing to Legacy helped fix this for a lot of my seamless transitions. 

This typically happens with botched expressions when references to other properties/ effects break down or the property holding the expression gets fed a wrong value or data type by the reference. Beyond that we can't really say much, but it seems to me you simply mucked up things with your template projects because you don't really understand what's going on in them, no offense. All you can do is therefore to enable caps-lock to suppress the rendering/ evaluation and hope you can successfully click away the warning. Otherwise you'll probbaly have to hard-reset your MacBook or manually terminate the process in the process list.

Mylenium