Similar Posts, Random Posts, Recent Posts, and Recent Comments have all been updated. The update is an interim bug-fix until the next real versions are ready. Two bugs are addressed.
One caused some users to get spurious characters displayed before the post listing.
The other… well the plugins were meant to work together but I’d managed to make them all fail if more than one of them were installed together! D’oh! I hope I’ve got that fixed now.
It’s a lesson to me to make sure I use the same configuration I recommend to others when testing plugins.