I have been trying to produce an outline of a stylised island using dissolve however there are internal "lines" that remain after I use dissolve? The hexagons that are being merged were created with the grid function so there shouldn't be any gaps present between them. I have tried "delete holes" however QGIS does recognise the lines as holes. QGIS is also showing the output as one large polygon too.
I'm a bit stumped as to why this is occurring. Alternatively is there is a different way to easily produce the outline of the polygons?
The below photos show the grid created input and the dissolve output with lines on it.