I am currently in the progress of building my second printer, and have encountered an odd problem. This is a SKR 1.3 mobo dual extruder running the latest Marlin 2.0.
Sending a M109 command to either T0 or T1 causes the second extruder to output the maximum possible value set in the Marlin firmware, in this case 260. So if I for instance send M109 S190 T0 to the printer, the T0 starts heating normally, but seconds later T1 returns that the temperature is at 260c.
This is really weird as M104 does not have this effect. I have searched the web and the firmware itself far and wide but have not been able to solve this. A bug, perhaps?