Reaper freezing with Roli Seaboard and Softube Parallels VST3i

[nepenthe]

Very specific issue:
- Launch Reaper with Roli Seaboard Block connected via USB
- Instantiate Softube Parallels synth (VST3i)
- record enable track
- input monitoring on

When I press a key on the Seaboard I see a note on in the meter, but following presses have no effect. If I click on the track (disable record enable, for example), Reaper will freeze.

I’m not sure what’s going on here but it only happens with the VST3 version of Parallels.

"
Heaviest stack for the main thread of the target process:
46 ??? (REAPER + 4980) [0x10e09e374]
46 NSApplicationMain + 777 (AppKit + 13206) [0x7fff2e213396]
46 -[NSApplication run] + 707 (AppKit + 202175) [0x7fff2e2415bf]
46 ??? (REAPER + 3709504) [0x10e426a40]
46 -[NSApplication(NSEvent) sendEvent:] + 352 (AppKit + 1983828) [0x7fff2e3f4554]
46 -[NSWindow(NSEventRouting) sendEvent:] + 349 (AppKit + 1991113) [0x7fff2e3f61c9]
46 -[NSWindow(NSEventRouting) _reallySendEvent:isDelayedEvent:] + 2738 (AppKit + 1994399) [0x7fff2e3f6e9f]
46 ??? (REAPER + 5652073) [0x10e600e69]
46 ??? (REAPER + 6212453) [0x10e689b65]
46 ??? (REAPER + 6356153) [0x10e6accb9]
46 ??? (REAPER + 6370961) [0x10e6b0691]
46 ??? (REAPER + 3727938) [0x10e42b242]
46 ??? (REAPER + 3755817) [0x10e431f29]
46 ??? (REAPER + 6356153) [0x10e6accb9]
46 ??? (REAPER + 6362870) [0x10e6ae6f6]
46 ??? (REAPER + 2391670) [0x10e2e4e76]
46 ??? (REAPER + 2425290) [0x10e2ed1ca]
46 _pthread_mutex_firstfit_lock_slow + 222 (libsystem_pthread.dylib + 6455) [0x7fff6b24d937]
46 __psynch_mutexwait + 10 (libsystem_kernel.dylib + 12386) [0x7fff6b191062]
*46 psynch_mtxcontinue + 0 (pthread + 9566) [0xffffff7f8362e55e]"