Download .mp4 from Google Photo using Google Drive API will get wrong md5Checksum - google-api

Question

When we try to download a file with an extension of .mp4 from Google Photo using Google Drive API, the downloaded file always has different md5 hash value with the md5Checksum field provided by remote metadata.
For example, assume there exists a file name video.mp4 on Google Photo. After we download the file using either one of the following URL:
(v2) https://doc-14-6c-docs.googleusercontent.com/docs/securesc/[SOME_VALUES]?h=[SOME_VALUES]&e=download&gd=true
(v3) https://www.googleapis.com/drive/v3/files/[FILEID]?alt=media
Both methods will download the file correctly on a local machine. The file size is also the same as the fileSize field of remote metadata.
However, the md5 hash value is inconsistent with the md5Checksum field of remote metadata. For example, if we enter $md5sum video.mp4 command, we may got 5cf9fb1bb88dc9bf38d1de5c9180dc4e video.mp4. This is not the hash recorded at remote metadata.
All other files work fine (size and hash are consistent), except for the files with an extension of .mp4. By the way, we use CURL to send a request to Google Drive API to download these files, instead of using any of Google Drive SDK.
Hope someone can help us, thanks!
[Update] more explanation
These files are from our customer's Google Photo. We don't know the exact way to reproduce such situaion. We provide the metadata of one of problematic file for your reference. (we remove some private information.)
{
"kind": "drive#file",
"id": "(REMOVED)",
"etag": "(REMOVED)",
"selfLink": "(REMOVED)",
"webContentLink": "(REMOVED)",
"alternateLink": "(REMOVED)",
"embedLink": "(REMOVED)",
"iconLink": "(REMOVED)",
"thumbnailLink": "(REMOVED)",
"title": "(REMOVED)",
"mimeType": "video/mp4",
"description": "",
"labels": {
"starred": false,
"hidden": false,
"trashed": false,
"restricted": false,
"viewed": false
},
"createdDate": "2016-10-10T11:42:25.000Z",
"modifiedDate": "2016-10-18T23:01:19.000Z",
"modifiedByMeDate": "2016-10-18T23:01:19.000Z",
"markedViewedByMeDate": "1970-01-01T00:00:00.000Z",
"version": "133589",
"parents": [
{
"kind": "drive#parentReference",
"id": "(REMOVED)",
"selfLink": "(REMOVED)",
"parentLink": "(REMOVED)",
"isRoot": false
}
],
"downloadUrl": "(REMOVED)",
"userPermission": {
"kind": "drive#permission",
"etag": "(REMOVED)",
"id": "me",
"selfLink": "(REMOVED)",
"role": "owner",
"type": "user"
},
"originalFilename": "(REMOVED)",
"fileExtension": "mp4",
"md5Checksum": "c5a208198614c34b6fc61186d025df77",
"fileSize": "15284923",
"quotaBytesUsed": "0",
"ownerNames": [
"(REMOVED)"
],
"owners": [
{
"kind": "drive#user",
"displayName": "(REMOVED)",
"picture": {
"url": "(REMOVED)"
},
"isAuthenticatedUser": true,
"permissionId": "(REMOVED)",
"emailAddress": "(REMOVED)"
}
],
"lastModifyingUserName": "(REMOVED)",
"lastModifyingUser": {
"kind": "drive#user",
"displayName": "(REMOVED)",
"picture": {
"url": "(REMOVED)"
},
"isAuthenticatedUser": true,
"permissionId": "(REMOVED)",
"emailAddress": "(REMOVED)"
},
"capabilities": {
"canCopy": true,
"canEdit": true
},
"editable": true,
"copyable": true,
"writersCanShare": true,
"shared": false,
"explicitlyTrashed": false,
"appDataContents": false,
"headRevisionId": "(REMOVED)",
"videoMediaMetadata": {
"width": 720,
"height": 1280,
"durationMillis": "43697"
},
"spaces": [
"photos",
"drive"
]}
As you can see, the md5Checksum field shows c5a208198614c34b6fc61186d025df77 in the metadata. However, the actual md5 hash value equals to 95be52d721e2f5d8d02650b27095d466 instead.