Hi, sorry for the late reply, I only have free time in short patches these days. This subject turned out to be quite a rabbit hole so I don’t plan to go further with it. The original g’mic filter “CRMT Tiles” is still present and functional, with an inpaint option to fix seams.
As @gubach mentioned, edges are a tricky problem. More so if you’re trying to fix up a re-usable vector map. The g’mic command I normally use to fix such issues is inpaint, but you must first construct a mask image containing only the “holes”. There’s a lot of related stuff here (and many other similar threads): Scanned image scratch removal with “ICE”