This is but another example of reloading issues discussed here that once again, resolve to use of FL dies -as a shortcut.
Two problems here that NS/body die users don't get into because:
1. We don't use/need expanders
2. We think about what it is that we're actually doing to our brass, while we specifically adjust for it. We choose our bushings, and measure our shoulders.. And everything works to a plan..
None of this slap hazardly running brass through a single die, and assuming it magically does it all correctly, unless results are so far out of whack that questions 'must' be asked about it..
But anyway, off my soapbox..
Even when you fix the sizing issues, that 338 trimming pilot will NOT work for sized brass, right?
So fixing a die won't help you there.
You'll need to trim pre-sizing or turn down the .338 pilot to about .334 for post-sizing use.
But, if you trim pre-sizing -while following with FL sizing, then case length will end up inconsistant. This is because FL sizing lengthens cases based on the amount of it's over-sizing.
So the solution to your original problem is use a correct size trimming pilot, post-sizing.
Turn it down, or use another that's right.