Why is my iPhone 15 Pro charging to 100% despite setting a battery limit of 95%?

Yes, if you read this support article, it explains that from time to time, the phone will charge to 100%, even with a battery limit set on purpose and for the overall health of the battery --> About Charge Limit and Optimized Battery Charging on iPhone - Apple Support

With a Charge Limit enabled, your iPhone will still occasionally charge to 100%. This is to calibrate the battery health percentage and ensure it shows an accurate reading. It is absolutely normal. But what we don't know is how often it will choose to. That is up to the smart algorithms which determine when to do so to ensure battery longevity based on your usage, conditions, etc. It could be weekly, monthly. When I used to set a Charge Limit, I saw it charge fully about twice a month.