What is the problem?
The print stops in short time steps and leaves a nasty blobs behind.
What did you already try to solve it?
I made a backup of the .octoprint folder and a new OctoPi/OctoPrint setup with restoring the .octoprint folder: No change.
I made a print in save mode: No blobs.
Uploaded an older backup of the .octoprint folder: Blobs reappear.
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)
OctoPrint version 1.3.9rc4
OctoPi version 0.15.1
Printer Prusa i3 MK2MM
Firmware 3.1.0
I see you have the PrintTimeGenius plugin installed. Try disabling that, see if the issue vanishes. If so, it's the same problem we just discussed on the feedback ticket for 1.3.9rc4 (discussion starts here) and some bug in the plugin.