it fixes the issue I am able to reproduce the problem (with 5.0.5 Pro Linux version). The inspection is actually active and the PEP8 checks are all enabled, I even got a blank line at end of file flag raised, but not an unresolved reference one:
help you fix your problem I am using PyCharm professional edition 2018.1 I am using remote interpreter via ssh. As a result, when I use shortcuts to Inspect Code (e.g. look at the source of a function I am using in the main script), the tab that opens refers to a file on the remote server /system/remote_resources/.../... , I found a solution that works for me.