Chrome Version: 57.0.2945.0
Chrome OS Version: 9034.0.0

Steps To Reproduce:
(1) Create several bitmap files (.bmp) of the same image size.
(2) Make all the timestamps of the files same.
(3) Copy the files to the /DCIM directory of a SD card.
(4) Plug it to a ChromeOS device. Wait until Files app and cloud backup details open.
(5) Dismiss the popped up "ready to backup" dialog. Do not click "back up" button.
(6) Make sure the "Status" field of the files are blank. (no Drive icon)
(7) Select one of the files. See the Cloud Backup button turns to (cloud with uparrow).
(8) Click the Cloud Backup button to backup the chosen file, and wait until backup finishes.
(10) Eject, unplug and plug the SD card again.

Expected Result:
Cloud Backup dialog says "%d files are ready to backup" where %d is total # of files minus 1, and shows a backup button.
The Cloud Backup button is (clould with uparrow), meaning that there are files that are not backed up.
In the Status column, only 1 file (chosen at step 7) is shown as backed up.

Actual Result:
Cloud Backup dialog says "All backed up".
In the Status column, all the files are shown as already backed up.
The Cloud Backup button is (clould with checkmark), meaning that it all the files has been backed up.
(Though other files are not actually copied to Drive.)

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)
Always, if we build files like this way.

What is the impact to the user, and is there a workaround? If so, what is
it?
The repro condition requires to have files with the exactly same timestamp in seconds and size, but different filename and contents.
Therefore this would not be so likely to happen with digital camera media (because files are typically jpeg format with varying size and would have different timestamps.)
However, devices that write raw image files or bitmap files may be more likely to be affected.
 

Chrome Version: 57.0.2945.0
Chrome OS Version: 9034.0.0

Steps To Reproduce:
(1) Create several bitmap files (.bmp) of the same image size.
(2) Make all the timestamps of the files same.
(3) Copy the files to the /DCIM directory of an SD card.
(4) Plug it to a ChromeOS device. Wait until Files app and cloud backup details open.
(5) Dismiss the popped up "ready to backup" dialog. Do not click "back up" button.
(6) Make sure the "Status" field of the files are blank. (no Drive icon)
(7) Select one of the files. See the Cloud Backup button turns to (cloud with uparrow).
(8) Click the Cloud Backup button to backup the chosen file, and wait until backup finishes.
(10) Eject, unplug and plug the SD card again.

Expected Result:
Cloud Backup dialog says "%d files are ready to backup" where %d is total # of files minus 1, and shows a backup button.
The Cloud Backup button is (clould with uparrow), meaning that there are files that are not backed up.
In the Status column, only 1 file (chosen at step 7) is shown as backed up.

Actual Result:
Cloud Backup dialog says "All backed up".
In the Status column, all the files are shown as already backed up.
The Cloud Backup button is (clould with checkmark), meaning that it all the files has been backed up.
(Though other files are not actually copied to Drive.)

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)
Always, if we build files like this way.

What is the impact to the user, and is there a workaround? If so, what is
it?
The repro condition requires to have files with the exactly same timestamp in seconds and size, but different filename and contents.
Therefore this would not be so likely to happen with digital camera media (because files are typically jpeg format with varying size and would have different timestamps.)
However, devices that write raw image files or bitmap files are more likely to be affected.
 

Chrome Version: 57.0.2945.0
Chrome OS Version: 9034.0.0

Steps To Reproduce:
(1) Create several bitmap files (.bmp) of the same image size.
(2) Make all the timestamps of the files same.
(3) Copy the files to the /DCIM directory of an SD card.
(4) Plug it to a ChromeOS device. Wait until Files app and cloud backup details open.
(5) Dismiss the popped up "ready to backup" dialog. Do not click "back up" button.
(6) Make sure the "Status" field of the files are blank. (no Drive icon)
(7) Select one of the files. See the Cloud Backup button turns to (cloud with uparrow).
(8) Click the Cloud Backup button to backup the chosen file, and wait until backup finishes.
(9) Eject, unplug and plug the SD card again.

Expected Result:
Cloud Backup dialog says "%d files are ready to backup" where %d is total # of files minus 1, and shows a backup button.
The Cloud Backup button is (clould with uparrow), meaning that there are files that are not backed up.
In the Status column, only 1 file (chosen at step 7) is shown as backed up.

Actual Result:
Cloud Backup dialog says "All backed up".
In the Status column, all the files are shown as already backed up.
The Cloud Backup button is (clould with checkmark), meaning that it all the files has been backed up.
(Though other files are not actually copied to Drive.)

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)
Always, if we build files like this way.

What is the impact to the user, and is there a workaround? If so, what is
it?
The repro condition requires to have files with the exactly same timestamp in seconds and size, but different filename and contents.
Therefore this would not be so likely to happen with digital camera media (because files are typically jpeg format with varying size and would have different timestamps.)
However, devices that write raw image files or bitmap files are more likely to be affected.