iPhone XR fully charge issue

hello gang,
so i recently got myself a new iphone XR and am loving it.
however, i noticed an issue while charging it's battery.
for some reason, i noticed that the battery never seems to get fully charged, and all i hear when i touch the battery status is battery charging 100%.
from what i know, voiceover should say on AC power indicating that the battery is fully charged
i even tried turning on airplane mode and charged it the entire night; but the battery never reached the 100% AC notification.
so i was just wondering if i'm doing something wrong, or does the iphone XR no longer announces the 100% AC power notification when fully charged,
any info or help would be greatly appreciated.
Thank you so much
arvind