When placing water in a cauldron, it uses the lava texture. Water is still in there, but the texture shows lava, and doesn't emit light. I have a lava cauldron in the same world, so it might affect this bug.
MCPE-171933
Incorrect Water Texture in Cauldron
Resolved
Duplicate
1
Thank you for your report!
We're tracking this issue in MCPE-170427, 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