Since Magnetic Field's duration was increased, the sound now lasts too short for level 4 field, by about 1 second.

These kind of sound effect should always be made looping sounds, because this is a reoccurring issue, since spell durations get changed pretty much in every patch.

If you want, I can just create a looping version for affected spells.

Here is a looping Magnetic Field.wav I created, by only using the original sound file from the game files (you can directly download it from here by right-clicking the player and save audio).