ContentVersion before trigger is not applying changes when uploading a new version of file from Files Tab

The 'before insert' trigger on the ContentVersion object won't apply any changes to a custom field when uploading a new version of a file from the Files Tab. The value set by the before trigger will be overwritten with the previous version's value.

If there's no default value set while uploading a new file, it will be null.

- Expected result:
Custom fields is populated with a designated value.

- Actual result:
Custom field isn't populated.

Steps To Reproduce:

(1) Create a custom field on the ContentVersion object (e.g., "Custom_Data__c", Text, 255 characters)
(2) Create an Apex trigger on ContentVersion with before insert and after insert events:
===================================================
trigger ContentVersionTrigger on ContentVersion (before insert, after insert) {
if (Trigger.isBefore && Trigger.isInsert) {
for (ContentVersion cv : Trigger.new) {
cv.Custom_Data__c = Datetime.now().toString();
}
System.debug(Trigger.new[0].Custom_Data__c);
}
if (Trigger.isAfter && Trigger.isInsert) {
System.debug(Trigger.new[0].Custom_Data__c);
}
}
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(3) Navigate to the Files tab in Lightning Experience
(4) Upload a new file and verify the "Custom_Data__c" field shows the correct timestamp in the file details
(5) Upload a new version of the same file
(6) Observe that the "Custom_Data__c" field shows the timestamp from the original file upload rather than the new version upload time