Before 1.19.80, the old world loaded did look fine. But after 1.19.80 update, the old world from version 0.9.0 until 0.11.1 loaded will have lots of errors.
Steps to reproduce:
Import and open the attached worlds:
,
Walk around and try to break/place blocks
Observed result:
You will walk too fast. Even if you die and respawn, that speed effect never stops. You will not be able to hit, break, and use anything that is near you.
Expected result:
You walk at normal speed. You are able to do everything a person with Member status can.
Notes:
It can only be reproduced in version 1.19.80 up to the current version.
Linked issues
relates to 2
Attachments
Comments 19

What specific device and version are you using?
Please do not pick every option for version, but only the one(s) you have actually tried.
Had you played this world in a more recent version than 0.9.0? If so, what version did you last play it in?
What specific device and version are you using?
Please do not pick every option for version, but only the one(s) you have actually tried.
Had you played this world in a more recent version than 0.9.0? If so, what version did you last play it in?
@unknown: Thank you for pointing that out.
I'm able to reproduce the 3rd issue, however I am unable to reproduce the 2nd and 4th issues (as the attached world is in Creative mode). Is there a world in Survival mode from 0.9.0 that can be used to reproduce those ones?
Reopened as I have obtained a copy of worlds created in 0.9.5 in both Creative and Survival modes. As I was unable to reproduce the issue with not taking damage and hostile mobs not aggroing when the player is in Survival mode, I have removed them from the report. If anyone happens to find a world that is affected with the aforementioned issues when upgrading from older versions directly to 1.21.2 or later, please leave a comment and attach the affected world to the report. If the file size is too large, please upload it somewhere else and then link to it here.
Greetings, my old worlds have the same issues. I am sure my worlds were played at 0.10.5 last time;
I took a video of gameplay, which contains:
The same speed effect both in survival and creative; it cannot be removed with commands;
Unability to affect blocks - which gets fixed with permission level changing;
Getting damage; the record is after changing permission level, there is a possibility it would not work before it;
Activating a creeper;
Sped up mobs from 2015 - newly spawned mobs have normal speed.
My device is RedmiBook Pro 14, Windows 11. I am sure the same issues happened on my mobiles, too.
Here is a link to the video: https://drive.google.com/file/d/1xWgMt83xMUGhSJQqr2s3ZUNd5R7fSGUc/view?usp=sharing
I also uploaded 2 files of worlds shown in the video:
[media]and
[media].
Please tell me if something is wrong: i just registered after finding the same issue as mine, to share my files.