I can't log into my world. I do have the wandering merchant in the area. (Adding this because I saw another similar report but in my case I have a different report)
This is all I got in the log
The game crashed whilst ticking entity
Error: java.lang.NullPointerException: Ticking entity
Related issues
duplicates
Comments
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It happened to me just now at 19w09a. same report. No wanderer this time. I was just fighting the raid at my house and it happened.
As you said you have a wandering trader: Duplicate of MC-143404. Please, always include the crash report, and search before posting.