I don’t know why, but the solution ended up being:
strTr = (strTr - (Number(t) + Number(2)))
So both had to be typecast (?) to numbers for it to work.
Also, the error was caused by participants rapidly clicking through. Thorough testing determined that was the cause. But I’m not sure why the feedback routine was then skipped entirely. While this doesn’t prevent participants clicking through, it DOES force them to see the feedback routine and significantly decrease the number of trials per block. Therefore, since the program is acting as expected now, I’m calling this bug fixed.