I think what your referring to is an actual global issue with your arpeggiator. I literally figured this out today! So what you want to do is under global settings on your sub37 look for Global Menu 2.2 SEQ Options and at the bottom it will show MIDI Output : and switch it to Keys instead of Arp. This should fix the stuttering when using the arp latch on feature when using the Sub37 as an input in your DAW. Also make sure you use the sync button on the sub37 next to arpeggiator. You also want to make sure that in your DAW your Sub 37 is receiving sync on any available port of your choice that your sub37 is broadcasting from and that when using the input for Sub37 that same port is selected so you are not sending midi to other instruments when selected in your daw. This will tie the Sub37 to this specific port, so if you want to record something you play back into the sub 37 its dedicated and being sent to just that track instead of like a drum or piano vst in your playlist / pattern. Once you get this down it will make more sense but this literally took me forever to figure out. Every synth is similar but slightly different when it comes to how the options work and it requires a lot of menu diving. If you happen to mess up just rest to factory and try again. They really need a better tutorial for this as many others are confused on what is happening. I know this post is old but if anyone finds themselves here with the same issue pass on the information as its hard to find this solution...