(Bug): EXR files fail to load from exFAT USB drives in Natron (but work in Nuke and with oiiotool)

[PixelPincher]

Make sure to follow our issue report guidelines

• I'm using the latest version of Natron (not required but recommended)
• I've restarted Natron and the issue persists
• I've run Natron via the command line and the issue persists
• I've followed the contributing guidelines to the best of my understanding
• My issue is not on the issue tracker or in a pull request already (go search for it and dig around a little bit!)
• This bug is reproducible

Natron version

Natron 2.5.0

Operating system

Windows 10 Pro

System specs

RAM: 32GB
CPU: Intel i7-3930K
GPU: GTX 770

Did you install Natron using the official installer?

• Yes, I used the official installer
• No, I installed from a binary archive
• No, I compiled Natron from sources
• No, I installed Natron via another method

Custom installation path

No response

What were you trying to do?

I was trying to read an OpenEXR image file using a Read node in Natron. The EXR files are stored on an external USB hard drive formatted as exFAT.

What did you expect to happen? What happened instead?

Expected: Natron should load the EXR files from the external drive as it does when the same files are stored locally.

Actual: Natron fails to read the EXR files when they are located on the exFAT-formatted external USB drive. However, if I copy the exact same files to a local internal drive, Natron reads them with no issues.

Step-by-step reproduction instructions

1. Prepare a valid EXR file (tested with 3840 x 2160, 4-channel, half-float OpenEXR).

2. Save the file to an external USB hard drive formatted as exFAT.

3. Open Natron and add a Read node.

4. Load the EXR file directly from the external drive.

5. Observe that the file fails to load (black viewer with 0x0 where resolution would be indicated).

6. Copy the same EXR file to a local/internal drive.

7. Load it in Natron again — this time it loads successfully.

Additional details

External Drive:
Samsung T7 Shield 2TB, USB 3.2
Drive format: exFAT

EXR info (via oiiotool --info):

Operating System: Windows 10 Pro

Internal Drive
Drive format: NTFS

I've tried every lossless compression type for EXR that Blender has: all with same result.
No OpenExr MultiLayer files were tested.

Nuke and Gimp were able to read the exr file off both internal and external hard drives with no problem.
Natron was able to read a png file of the same image off both internal and external hard drives with no problem.

[PixelPincher]

This is very similar to:
#848