"blobs" on the outside shell - how to get rid of them

How to tune outside shell to get rid of the seem blobs? I tried to change retraction, but with no visible success.

that may be a firmware issue. is this a bowden or direct drive? what is the firmware?

It is MARLIN based on 2.0.9

have enabled linear advance and experimented with K factors? or whatever the latest state of the art nozzle pressure management is available?