My iPhone 16e charge to 100% when I have it set to 80%

That's correct. Apple specifically suggests your iPhone will still charge to 100% on occasion even with a charge limit set. Read this --> About Charge Limit and Optimized Battery Charging on iPhone - Apple Support

Contained in this link is the following:

With iPhone 15 models and later, if the charge limit is 100 percent, you can also turn on Optimized Battery Charging. Your iPhone has these settings by default.

Your iPhone will charge to within a few percentage points of your chosen limit and then stop charging. If the battery charge level drops more than 5 percent while connected to power, charging will resume, again charging to within a few points of your chosen limit.

If iOS determines that a charge limit will help preserve your battery's lifespan, you'll see a recommendation. For example, you might see "Based on your iPhone habits, a charge limit of 95% is recommended to help preserve your battery."

If you have Charge Limit set to less than 100 percent, your iPhone will occasionally charge to 100 percent to maintain accurate battery state-of-charge estimates.

All perfectly normal and expected in order to calibrate your battery. Just set it and forget it, your iPhone has advanced charging and battery optimizations designed to prolong the battery life.

Don't worry about micromanaging your battery, just use your phone like it was made for and enjoy. The one drawback with the 80% charge limit is in most cases you are always starting your day with 20% less usage than anyone else that starts with 100%.

This happened on my dads iPhone 16e.

Step1— wrote:

This happened on my dads iPhone 16e.

So read the answer from myself and Mac Jim ID above to understand this is normal.

the same thing always happen with me as well on my iphone 16 pro max i thought it's works like that.