What i did / Steps to reproduce

                shapeMarker = ShapeMarker.builder()
                        .shape(new Shape(vector2ds), height)
                        .label(label)
                        //.minDistance(125)
                        .maxDistance(Double.MAX_VALUE)
                        .build();

                markerSet.getMarkers().put(id, shapeMarker);

Expected result

They should always display.

Actual result

They're only visible when the map is blurry (not fully rendered).
Once the chunks start rendering, the markers disappear.

Context

BlueMap version 3.3
git-Paper-111 (MC: 1.19.1) (Implementing API version 1.19.1-R0.1-SNAPSHOT) (Git: 02831e3)
No mods.

That was it, thanks! Do POIMarker's support html?

No, they don't .. only the detail or html from the other markers can have html in it .. the label can't ^^

I am guessing they just hide behind the terrain .. so adding .depthTestEnabled(false) to the markers should fix your issue :)