When witch trying to kill the undead creature with the maximum hp, she is starting throwing the splash poison potions, which cannot inflict damage to undead creatures.
Witch should throw splash potions of regeneration or healing, but not the poison potions, which heals undead creatures instead of hurting them.
1. spawn a witch near the undead creature(I prefer zoglins, because they can easily aggro witches (it also works with skeletons(and other udead creature(if you able to aggro witch against the creature somehow))))
2. after witch will be aggresive towards the undead creature it will start throwing splah poison potions, which are harmless towards undeads
Thank you for your report!
However, we are already tracking this issue, and this report is a Duplicate of MC-94281, which is a report that has not been resolved yet.
If you want, you can upvote the parent ticket, and enable watching to receive any updates about it - if you believe you have any information that may be important for this issue, please leave a comment on the parent. Please also use the search function in the future to prevent duplicate reports.
Quick Links:
📓 Issue Guidelines – 🛠 Community Support – 📧 Customer Support – ✍️ Feedback and Suggestions – 📖 Game Wiki
💬 Mojira Subreddit – 💬 Mojira Discord