Octoprint crash into bed when start a Gcode file!

Hi everyone!
I just finished my Kossel XXL, with ramps (marlin 1.04) and RPi2 (Octoprint last version).
Is not the first kossel i do and i used on everyone the same fw as above.
In the past i used octopi also (Don't remember wich version, but more than an year ago.

- the Printer works perfectly in hardware and the software works grate when i use manual moves;
- i used octopi for calibrating it so i know it is configured and working;
But now i'm running in a strange issue:
- i generate a gcode from cura in desktop (same version and profile ad other printers, I upload it via browser to octopi, i press print;
- the Printer heats io and when it starts to move, does a G28 and then with glitching fast moves go straight in the bed! Continuing pushing on it!

Why is this happening? I tried to generate several times the gcode file, but every time is the same result!

The things i'm evaluating are 2:
- misconfiguration of some "resend 'ok' etc.." in octopi settings which can delay the command sent to the primter;
- the gcode is slow to be "played" because it is on an external USB (the pi boots from usb, where both the system and the gcode are)

Any trick?
Thanks in advice to everyone who will reply!

When you calibrate the printer and then have a G28 in the startcode of Cura, all the calibration settings are lost.

Thank you o_lampe, but i solved...i Don't really know why but the problem was because of the microstep set to 1/32 and the step/mm to 200 (i think because it's only an 8bit mega2560). Infact, simply lowering the step/mm to 100 (supposing the hardware was at 1/16) the problem disappeared. So i changed the jumper configuration for setting 1/16 microstepping and everything worked perfectly!

Anyway changing the jumpers i noticed that also the extruder microstepping was setted to 1/32 in hardware! in software i supposed it at 1/16 (while setting the extruder's step/mm), but it was mooving the correct distance also with this calculation error. Why?

About the calibration i usually use G30 A and then M500 for saving, as i read that g29 doesn't apply any effect...maybe i have an old version of marlin? (I'm using the 1.04 because i didn't find a newer version...the fork I was referring to is closed)