Ah, it looks like the blood ritual that I performed on the last full moon dealt with them.
I didn't do anything, so I guess that it was just the same person.
BTW, the main blocker for me taking action was that I never got around to compiling the table of homographic characters and their ASCII counterparts. If this crops up again, it'd be helpful if someone would compile a nice plaintext " -> " table.
OK, we will try to assemble a table but in the meantime, can we just add them to the rules? So if we spot some just directly report them without trying to find a solid proof of plagiarisms?