Repeated transfer issue and copy of same iPhone .mov files gives different results / changes files

Have been doing iPhone transfers to Windows through USB for years with Directory Opus.
Was able to confirm successful transfers using Directory Opus compare tools.

Now working with iPhone 8 running iOS 11.2.1 from Windows 10 Pro 64bit using DO 12.7.
Having worked around iPhone security and time out issues, I tried to use the old techniques for transfer and confirm.

Problem 1:
I was not able to transfer large iPhone DCIM directories with DO, at about 2G of transfer, DO transfer or sync dialog would close and the transfer would be incomplete.
Using Windows File Explorer, the transfers do complete.
Setting DO advanced setting mtp_enable to false accomplished the same thing, the transfer succeeded.

Problem 2:
Using Windows File Explorer or DO with mtp_enable true or false, successive transfers of the absolutely unchanged files in the iPhone stores DIFFERENT/MODIFIED .MOV files in Windows.
i.e. iPhone IMG_4748.MOV file copied to Windows the first time is different than copies of the file the second and successive times.
The movies do play and look the same but the files are NOT identical.
Same size and date but not at byte level.
It always happens with .MOV files, .JPGs may or may not have problem.
This may be connected to the new iOS 11 HEIC file format and some conversion process that takes place moving to Windows to make it Windows viewable.
This, of course, leads to no way to absolutely confirm the file was successfully transferred.
VERY unexpected results.

Suggestions or ideas would be greatly appreciated.

Problem 1: Keep using mtp_enable=false if it fixes things for you.

Problem 2: If both Opus and Explorer are doing the same thing, it's something that either iOS is doing on its side, or that is happening at a fairly low level in the Windows MTP stack on the Windows side. Probably not something we can change.

Have you identified how the files are different? It is probably a timestamp which will make it different every time.