At the beginning of a turn just after your soldiers used their RF, the 'Toggle RF' button will sometimes indicate the same icon as it does when you can't turn RF on. Clicking on it does nothing, so you can't turn RF off.

Selecting a soldier who is not on RF mode (e.g. a rocket launcher) will jolt the game out of this state.

The soldiers who have RF on will now have the 'RF on' icon displayed on the button, and clicking it turns RF off as expected.

Also (maybe related), at the beginning of the first turn, it is sometimes (not always) possible to switch RF on for rocket launchers / grenade launchers. The game hangs if you end the turn with it on though.

Here's a log with ufo +set developer 1, both bugs occurred though obviously I haven't a clue if they show up...

https://dl.dropboxusercontent.com/u/1257491/ufoconsole.log

Debian 64 bit, built from master.

<source lang="bash">
% git log -1
commit 7aeeadcb4fd469ca0544d70aa77b0acb7990fb34
Author: Igor Gritsenko <xenomorph@thoradin.no-ip.org>
Date: Fri May 30 11:24:39 2014 +0300

* [UI2:UFOPedia] Small model is now hidden when the big picture is chosen.
</source>