The 1.21 Change Log has the following update in it:
https://www.minecraft.net/en-us/article/minecraft-java-edition-1-21
----------
ENTITY DATA
PROJECTILES
Arrow-like projectile data now contains a weapon field containing an Item Stack representing the weapon the projectile was fired from
The ShotFromCrossbow field has been removed
Removed power NBT tag and replaced it with acceleration_power tag with a number value that control the projectiles acceleration (and maximum speed)
This change affects the following projectiles; dragon_fireball, large_fireball, small_fireball, fireball, breeze_wind_charge, wind_charge, wither_skull
----------
There seems to be an unintended change now to how much water affects the trajectory of wither skulls. Please see the attached picture showing a big change in the height gain being affected.
Linked issues
Attachments
Comments 2
Thank you for your report!
We're tracking this issue in MC-272942, so this ticket is being resolved and linked as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
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 (Technical Issues) – 📧 Microsoft Support (Account Issues)
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki
Probably relates to MC-272942.