This is a mod collision problem as I couldn't reproduce none of your reports. Which other mods (apart from PM) are you using? (I guess it could be Poland rebuilding).
Junior Beta-Tester since 2.26
Translator of Spanish, Catalan, Euskera and Galician.
Thanks for showing me this erbkaiser. The hole is there even in standard Promods but the trees are indeed a problem caused by my mod due to an accidentally deleted vegetation sphere that was used to hide them. Will re-add it and plug the hole in the process later this day and update the addon.