The bug
Blocks at y=-64 don't show on a map (item), but their shadows (and highlights) still do.
[media]Work around
Place transparent blocks (barrier blocks, glass etc) above the affected area. (Warning: This can cause a huge amount of lag if done all at once (another bug?))
This however has the side affect of removing the void background colour (gray) (another bug?) and removing their shadows and highlights
Work around shown by Alex Eade
Comment: https://bugs.mojang.com/browse/MC-134002?focusedCommentId=933604&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-933604
Linked issues
is duplicated by 5
Attachments
Comments 9
Found a workaround to this bug while applying a workaround to MC-162253.
All I did was place a layer of transparent blocks (ie. glass, barrier blocks) over the area I wanted to show on the map. I did this at y = 255 but from a little bit of testing it seems like any y value will work, even 1 block above the issue at y = 1.
Done on version 1.16.4/1.16.5 on Java Realms.
Confirmed for 1.13.1.