To be honest, Ive always had this problem back from v3. Im using it on a Rostock Max V2 and, as an example, if I clock Extrude in the Machine Control Panel more than say twice, it just stops responding. I then have to hit Disconnect then go again. Same with Macro's eventually just stops.
Actually printing however seems fine.
Other programs don't have this problem as I use them to calibrate the Rostock extensively, its just S3D.
I've been able to ignore the problem and work around it (ie manually pushing the filament into the hotend) but now Im trying out the Prometheus System (a dual extruder to 1 hotend), which introduces its own new Macros which, as feared, as just experiencing the problem too.
Ive tried No, Software and Hardware flow control and 63 and 127k cache. Anyone else with this issue or any ideas?