Okay I believe I figured it out -- if a tax expert wants to confirm, feel free.
Code P indicates "Excess contributions plus earnings/excess deferrals taxable in 2023."meaning it's reporting an excess contribution made in a previous year that you are taking out. The reason you typically amend is if you took a deduction for the previous tax year for that excess contribution you now need to amend your previous tax return so you don't get the deduction (after all it was excess and you're taking it out for that reason).
The second reason you may need to amend is if during the time in between if you made any capital gains on the excess contribution. That would also be a reason to amend your old tax return so that the capital gains can be reported appropriately (this would naturally show up as taxable amount on your 1099-R form)
Had I taken a deduction on this in my previous year tax return and/or made capital gains, I would have to amend. You can confirm if you took a deduction by looking at your previous year's tax return Form 1040 Schedule 1. I am not a tax expert.
