I was the only person online when these errors occurred, so I know for certain these caused crashes. Most of this is likely to be out of our range, i.e. we'll have to report this bug to FAWE or WorldEdit, but here it is here anyways since it affects the server.
WorldEdit commands which contain the exclamation point (!) used along with an id-style blocktype will cause the server to crash. //replace also hasn't been working properly with ids, sometimes it skips over blocks it should be catching, which might be related since ! just negates the selection. If the normal blocktype selection is bad, its negation will be worse.
WorldEdit commands which include the 1.13/1.14 result of chat auto correcting (default is Tab) will also cause a server crash. These objects contain the section sign (§) as part of their coloration, which is recognized as an invalid char on the server.