My ability to investigate this is very limited unfortunately.

I reckon a lot of that was probably to do with the building render perhaps? Unless you were doing something else.

Nah, just kind of standing around. Maybe poke it with jvisualvm. This could also be me derping.

After running a GC dump in Java VisualVM for about an hour the other day and an hour today I didn't notice anything related to Harvest Festival, so closing this for now!
If anybody else experience anything similiar we will take this up again :)