Are you sure it will find an element with those Block Id and Transform values?
Also it may not work correctly on Event Tick, because For loop may be going more than one tick, before it removes index.
Anyway calling loop on Event Tick may lead to unpredictable results, especially if that loop is expected to run for large number of iterations and/or process complex data. Basically there will exist multiple instances of this function, all processing same value (your array).
Try redesigning your code to not call this function every tick and then comment, if problem persists.