Why are some metadata changed "automatically" by Digikam?

Hi everyone,

I am using Digikam to manage my pictures, and more specifically to add some tags - so I can easily find some pictures. My Digikam instance is configured to manipulate Exif, XMP, … with exiftool

I noticed that when I add a tag to a picture, several Metadata are changed, and I don’t understand why.

For example, for a picture to which I added the Subject Party:

|
|
|----|

Original Updated
Composite:HyperfocalDistance 3.22 m 3.24 m
undefined ---- ----
Composite:ScaleFactor35efl 4.4 4.3
undefined ---- ----
ExifIFD:BrightnessValue -5.454663662 -5.454663633
undefined ---- ----
ExifIFD:ComponentsConfiguration Y, Cb, Cr, -
undefined ---- ----
ExifIFD:FlashpixVersion 100
undefined ---- ----
ExifIFD:LensInfo 2.220000029-5.960000038mm f/1.6-2.2 2.220000029-5.96mm f/1.6-2.2
undefined ---- ----
IFD0:YCbCrPositioning Centered
undefined ---- ----
QuickTime:MediaDataSize 1774314 1772898
undefined ---- ----
System:FileModifyDate 2025:08:19 21:02:43+02:00 2025:08:21 18:11:09+02:00
undefined ---- ----
System:FileName IMG_2437_2.HEIC IMG_2437.HEIC
undefined ---- ----
System:FileSize 1810 kB 1809 kB
undefined ---- ----
XMP-dc:Subject Party
undefined ---- ----
XMP-mwg-rs:RegionAppliedToDimensionsH 3024
undefined ---- ----
XMP-mwg-rs:RegionAppliedToDimensionsUnit pixel
undefined ---- ----
XMP-mwg-rs:RegionAppliedToDimensionsW 4032
undefined ---- ----
XMP-mwg-rs:RegionAreaH 0.142523383
undefined ---- ----
XMP-mwg-rs:RegionAreaUnit normalized
undefined ---- ----
XMP-mwg-rs:RegionAreaW 0.106892535
undefined ---- ----
XMP-mwg-rs:RegionAreaX 0.853608981
undefined ---- ----
XMP-mwg-rs:RegionAreaY 0.546550853
undefined ---- ----
XMP-mwg-rs:RegionExtensionsAngleInfoRoll 370
undefined ---- ----
XMP-mwg-rs:RegionExtensionsAngleInfoYaw -41
undefined ---- ----
XMP-mwg-rs:RegionExtensionsConfidenceLevel 0
undefined ---- ----
XMP-mwg-rs:RegionExtensionsFaceID 1
undefined ---- ----
XMP-mwg-rs:RegionType Face
undefined ---- ----

Why are all those tags updated ?
Is there a configuration in Digikam to stop it from updating those ?

Thank you in advance for your help on understanding this !

Nice day,

C