It is definitely a bug! You find it also on https://tiddlywiki.com/ (not prerelease)
Go to https://tiddlywiki.com/ Recent tab search (using ctrl-f i.e browser tool) for e.g the tiddler ExternalImages - this is the last title for 2014. After it comes 2020 again. <:-) -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to tiddlywiki+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/322ff3da-729c-421e-a3e5-47d55b888c39%40googlegroups.com.