It must be hot or cold extrusion allowed in 0.92. Also make sure extrusion is not longer then allowed extrusion distance. Here 500mm could be too much. STart with 5mm or 50mm.
There are relative and absolute positions. Extruders normally are in absolute position mode, so first goes to 850 and next to 300 which is -550 relative to last, so it goes backwards. Use G92 E0 before a e move command so it does what you expect.
Comments
GCode::executeFString(PSTR("G1 E850 F2000 S1"));
...
GCode::executeFString(PSTR("G1 E300 F1000 S1"));
The first gcode runs perfect but the second rotates the filament motor in reverse order even if i change E300 to E-300.
Just a hint or an explanation.
Thanks
Sooner or later i'll buy you a beer.