after setting up an automated pumpkin farm, i found that several stacks of pumpkins were incompatible with farmer trades. upon further investigation, i found that placing and mining the pumpkins while facing north fixes them. the main problem is that a single "wrong" pumpkin will mix into a normal pumpkin stack and poison it, making all 64 pumpkins untradable until they are placed and mined while facing north.
Thank you for your report!
We're tracking this issue in MCPE-105540, so this ticket is being resolved and linked as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki