Portra 400 4x5 sheets stuck

[Misko78]

Hi all,
I’m having a post-processing issue for the second time.

After developing Kodak Portra 400 sheet film and letting it dry for a few days, I store the dry sheets in the original film box. After some time, I notice that some sheets become stuck together, almost as if they were glued, while others are completely fine.
All sheets are placed in the box oriented the same way. There’s no visible residue, but the sticking is strong enough that I’m concerned about damaging the emulsion when separating them.
What could be causing this issue?

For context:

• Film is developed in a Jobo CPE2 Plus with lift
• Chemistry used: Fujihunt C-41

Any insight would be greatly appreciated.

 

[gbroadbridge]

I would suggest humidity is the issue In a closed box.

Best practice is to store individually in archival sleeves

 

[BrianShaw]

Could be that they weren’t fully dry.