I have spent so much time trying to get Ableton’s arpeggiator and clocked LFO’s to stay on rhythm via daw (ableton) and I don’t think it’s possible. Switch patches at any point, off, try anywhere a few minutes into the timeline, off, change bpm in Ableton (like changing songs without stopping), off. I gave up. I use abletons arpeggiator and gave up on clock synced LFO’s. Every time somebody tells me it works for them I proceed to see either no evidence or a video of a ripping fast arpeggiator that would be impossible to identify the accuracy of.
As far as “dropped notes”, if you mean sending midi notes to the Rev 2 froM ableton, I’ve had no problems with that but can think of some ableton related reasons that could cause it. (Like is the note starting slightly before the midi track and therefor the “note on” isn't present when you launch the track).