Octoprint wants to change filament every x meters

Hi
I have a Prusa i3 mk3 and if i print one g-code file from the internal SD card it works great.
If I print the same g-code file from octoprint it inserts a filament change every x meters of filament.
I can't find the M600 command in the g-code file that tells the Prusa i3 mk3 that a filament change should be done.

But if I look at the Terminal windows it says:
Send: N68730 G1 X164.153 Y49.733 E0.517798
Recv: ok
Send: N68731 G1 X163.989 Y49.755 E0.0046
109
Recv: echo:Enqueing to the front: "G1 E-3 F200"
Recv: echo:Enqueing to the front: "G1 E3 F200"
Recv: echo:Enqueing to the front: "M600"
Recv: echo:busy: processing

So suddenly a M600 is inserted by Octoprint, but WHY?

Octoprint version:
OctoPrint 1.3.9 running on OctoPi 0.15.1
Running an a raspberry PI 3

So what could be the problem?

Which plugins are you using?

It is really hard to tell what the problem may be without the logs. The way it looks from what you posted, the printer executed the M600- since there is no Send: M600 command

I did a reimage of the SD card and started all over again and it now seems to work. I have now printed the same g-codes that had problems before and now they work perfectly.

Thanks all.

This. Enqueing [...]: "M600" is the printer deciding it wants to swap filament, not OctoPrint. If this machine has a filament sensor (you sadly refused to tell us what printer this is happening on), it might be triggering falsely, causing this behaviour. In that case, try to disable it and see if that fixes it.

@foosel I've seen companies try to use those tiny blade microswitches whose width is a small fraction of the 1.75mm of the filament itself. It's very easy for the blade to just slide past the filament at times, triggering a false filament-out condition.

Even if you regard engineering as simply making a product as cheap as possible without failing during the warranty period, saving a half a cent on a microswitch to have it not work half the time has to be viewed as an engineering fail.

I was quick to critique that particular design decision on the Robo 3D to them in person. It's sad when you see this level of stupidity in a printer.

I'd drop the "in a printer" part. It's sad all over the place. But yeah, you'd think in a printer they wouldn't do something that would increase their support costs, since most printer companies struggle to make ends meet if they're not in China or are selling a premium product where those kinds of design decisions are not going to be well received.