I get the following error when running prepDE.py on stringtie estimate output:

Traceback (most recent call last):
  File "./prepDE.py", line 255, in <module>
    geneDict.setdefault(geneIDs[i],{}) #gene_id
KeyError: 'STRG.337.1'

I only get this for one sample out of fifteen. I run the HISAT2 > Stringtie workflow as described in Pertea et al. (2016). I want to feed this into edgeR. Is there another option in case I can not resolve this problem?

Additional question: What is the difference between MSTRG and STRG?