NPCs generated by citizen plugins are sometimes visible and sometimes not visible.

[RangFarm]

There are NPCs that you can see when you reconnect, but there are still NPCs that you can't see. I am using the latest version of Mirai. NPC with type set to animal can be seen well.

[etil2jz]

This is an issue with Petal's multithreaded entity tracker (see Bloom-host/Petal#3).
You can disable it in mirai.yml (will work) or try to use a Citizens dev build (could work).

[RangFarm]

It's resolved! Thank you for making a good bucket

[MrButtersDEV]

It's resolved! Thank you for making a good bucket

What option did you go with? Dev build or disabling it in the yml?

[RangFarm]

Yes, that's right! I changed it from true to false XD