Hi Jurgis, sorry to hear about that, that sounds frustrating. So far we’ve been unable to reproduce this with the latest version of Reaper, but it might be helpful to have some more information about your system.
The next time this issue happens, could you right-click the Eventide logo, and then choose “Copy Support Information to Clipboard”, then paste it into a reply? That should give us a better sense of what’s happening. (It sounds like there’s some issue with the internal state)