[Android Software Development] osm0sis:
Wellllll I think we have our answer!

--- before/all_files_with_sizes_fixed.txt	2023-09-21 23:45:06.112999838 -0300
+++ after/all_files_with_sizes_fixed.txt	2023-09-21 23:45:24.556999831 -0300
@@ -57,7 +57,7 @@
/product/etc/permissions/com.google.android.as.oss.xml 4.0K
/product/etc/permissions/com.google.android.as.xml 8.0K
/product/etc/permissions/com.google.android.dialer.support.xml 4.0K
-/product/etc/permissions/com.google.android.googlequicksearchbox.xml 0
+/product/etc/permissions/com.google.android.googlequicksearchbox.xml 12.0K
/product/etc/permissions/com.google.android.gsf.xml 8.0K
/product/etc/permissions/com.google.android.keep.xml 4.0K
/product/etc/permissions/com.google.android.maps.xml 4.0K
@@ -512,7 +512,7 @@
/product/overlay/TrebuchetOverlay.apk 12.0K
/product/overlay/TrebuchetQuickStep__auto_generated_rro_product.apk 12.0K
/product/overlay/Updater__auto_generated_rro_product.apk 12.0K
-/product/overlay/VelvetOverlay.apk 0
+/product/overlay/VelvetOverlay.apk 4.0K
/product/overlay/WifiResCommon.apk 16.0K
/product/overlay/framework-res__auto_generated_rro_product.apk 2.4M
/product/overlay/org.lineageos.platform-res__auto_generated_rro_product.apk 12.0K
@@ -538,7 +538,7 @@
/product/priv-app/SettingsIntelligence/oat/arm64/SettingsIntelligence.odex 32.0K
/product/priv-app/SettingsIntelligence/oat/arm64/SettingsIntelligence.vdex 32.0K
/product/priv-app/SettingsIntelligenceGooglePrebuilt/SettingsIntelligenceGooglePrebuilt.apk 7.9M
-/product/priv-app/Velvet/Velvet.apk 209.1M
+/product/priv-app/Velvet/Velvet.apk 385.9M
/product/usr/keylayout/Vendor_045e_Product_0719.kl 4.0K
/product/usr/share/ime/google/d3_lms/ko_2018030706.zip 4.3M
/product/usr/share/ime/google/d3_lms/mozc.data 8.6M

2023_09_21_23_06_26: - Restoring Velvet
2023_09_21_23_06_27: - /system/product/priv-app/Velvet/Velvet.apk copied, Size: 386M
2023_09_21_23_06_27: - /system/product/overlay/VelvetOverlay.apk copied, Size: 4.0K
2023_09_21_23_06_27: - /system/product/etc/permissions/com.google.android.googlequicksearchbox.xml copied, Size: 12K
2023_09_21_23_06_27: - /system/etc/permissions/Velvet.prop copied, Size: 4.0K
2023_09_21_23_06_27: - Searching for build.prop in /postinstall/product /postinstall/system
2023_09_21_23_06_28: - Setting Property ro.opa.eligible_device to true in /postinstall/product/etc/build.prop
2023_09_21_23_06_28: - Adding ro.opa.eligible_device to true in /postinstall/product/etc/build.prop
2023_09_21_23_06_28:
2023_09_21_23_06_28: - Restoring WebViewGoogle
2023_09_21_23_06_28: - Deleting aosp app product/app/webview
2023_09_21_23_06_28: - Checking if /postinstall/system/product/app/webview exists
2023_09_21_23_06_29: - Checking if /postinstall/product/app/webview exists
2023_09_21_23_06_29: - Found, deleting /postinstall/product/app/webview
2023_09_21_23_06_29: - Checking if /system/product/app/webview exists
2023_09_21_23_06_29: - Checking if /product/app/webview exists
2023_09_21_23_06_29: - Force Deleting webview
2023_09_21_23_06_29: - /system/app/WebViewGoogle/WebViewGoogle.apk.gz copied, Size: 41M
2023_09_21_23_06_29: - /system/product/overlay/GoogleWebViewOverlay.apk copied, Size: 24K
2023_09_21_23_06_29: - /system/app/WebViewGoogle-Stub/WebViewGoogle-Stub.apk copied, Size: 16K
2023_09_21_23_06_29: - /system/etc/permissions/WebViewGoogle.prop copied, Size: 4.0K

Looks like your hunch was correct and it ran out of space while restoring Velvet.apk, so the next 2 files end up zero-sized. Then Webview must have cleared out the space needed in product so Velvet could be dirty flashed after the OTA. Oddly your addon.d log still doesn't show an issue.. maybe it should log the sizes of both the source file before copy then the destination file after copy?

Connecting the dots from all of our conversation, I bet this is the new one-at-a-time addon.d-v3 behavior biting us in the ass, and you likely need to implement something to do all the removals during pre-restore like I hypothesized!