Error related to unpickling when running in parallel (HPC-resources)

**Description of the error**
The same unpickling error as we had it earlier appeared when I tried to run MDMC on a super-computer using slurm-scheduler.

**Describe the expected result**
Successful run

**Describe the actual result**
Many error messages

**Suggested fix**

**Additional details**
I was running it on one resource yesterday. Today I will try another one with graphic cards and see if the same error can appear.