Just found the answer on the apple forum.
The problem apparently is the change of formats from HEIC (High Efficiency) to JPG. To change this you need to go in your iPhone to Settings > Photos and on the bottom under "Transfer to Mac or PC" select "Keep Originals".
After doing this I kept having problems with the Photos app but I did a "Repair" and "Reset" on Windows 10. Settings > Apps > Apps & Features > Photos app > Advanced Options and it got fixed.
I tried the Photos Sync and copying from File Explorer and both worked. Hope this helps!
As an extra, if you want to stop taking pictures in HEIC on the iPhone go to: Settings > Camera > Formats > Most Compatible.