During the startup script I like to purge material by issuing a G1 E25 F300 instruction. However more often than not when S3D executes that command the extruder unloades filament and I end up with several 10's of mm filament missing. Frequently this follows a previous print where the purge operation worked as intended, so I'm puzzled about why this isn't a robust operation.
I haven't managed to figure out why this is happening - can someone help?