Existenter

Your Name: Existenter
Coordinates: Home coordinates of my base are x 2184, z -2314, y 63, but issue is located on top adjacent mountain (between my base home point and the world border and only a few blocks away from the world border; unfortunately I can not think of a way to find out the coordinates of the chunk in question, but it should definitely be within one of the chunks immediately adjacent to the world border).
Time/Date: Sep 23, 2018, ca. 11:00 AM (GMT+2; CEST)
Description of Issue: After placement of an Astral Sorcery containment chalice, two lightwells, and putting two rock crystals into them to create liquid starlight, both ShinyPorygon and me keep getting kicked from the server as soon as we enter the area with the following error message: "connection lost: illegalArgumentException: Unknown meta type 15 @ net.md_5.bungee.entitymap.EntityMap:200". I assume that somehow a particle or entity is created/requested that the server can't handle, thus kicks all players entering this area.
Would it be possible to either remove those items, or to reset the chunk(s) in question (I. e. that/those next to the world border)?
Thank you!
Screenshots (Optional): (none)