Hi Phil
Have you had a look at the file in mesh mixer, it may reveal deficiencies.
I have been printing Eclipson models with almost no problem following their profile. Planeprint Icon has given me a number of problems even when following their profiles, some have been due to retraction, ended up fitting direct drive and e3d v6, retraction 1.25mm and 25mm, ender 3 . the standard ender setup was causing holes in the prints due to the retraction/ reload requirements. Also need to tune for each filament even the colour can change the result. Interested in your fix.
hope this helps
Barry