Octopi disconnect when changing filament

I use octoprint (1.4.0) on a raspberry pi, connected to a Creality CR10.
I wanted to print something with two colors, so I added a post-processing script : filament change in my slicer (Cura 4.6.1).
I imported the generated gcode on octoprint and launched the print
At the given height, all was going correctly, the printer stopped printing, and beeped to alert me to change the filament.
But after doing that, I was not able to resume the print.
Octopi did disconnect itself from the printer (because it didn't receive any response from the printer).
Even after having manually reconnect octoprint to the printer, all the buttons (print/pause/cancel) are greyed, so I can't do anything, and in the meantime, the temperatures were falling...

Is this something to do to prevent octoprint to disconnect when the printer is in pause?

Please upload the octoprint.log and serial.log

I made another attempt with a tiny object.
Same result
Here are the corresponding logs, thanks!

octoprint.log (32.4 KB) serial.log (16.5 KB)