FL Studio as VSTi in Reaper - missing first note while in Song Mode?

So I have FLS running as a VSTi in Reaper. I create some beats in pattern mode, switch to song mode and paint the beat patterns into the FLS playlist. I do this in while Reaper is in loop mode of course, repeating a certain part of the song. But any 'hits' occurring, in any pattern, on the very first beat of the loop are NOT SOUNDED by FLS. This doesn't happen while in pattern mode. Anyone have any experience of this? Also, is there a way to trigger the different patterns from Reaper, by sending MIDI messages through to FLS, instead of using the FLS sequencer?

same problem here.

anyone managed to navigate this issue?