This might be thrown in NBT reading:
http://openeye.openmods.info/crashes/3ad79bacc6a1e256fa2138632e35bd87

This line for example will trow this error when a creativetab is removed after reloading:
https://github.com/Dynious/RefinedRelocation/blob/master/src/main/java/com/dynious/refinedrelocation/grid/FilterStandard.java#L406

Just need to add array size checks.