Missing segs/invalid data errors in console

I have three maps that are producing errors that say the nodes need to be rebuilt. One says 'GL nodes contain invalid data' and the others say missing segs counted in GL nodes.' Saving the file and running the maps seems to clear the problem but they always come back again, no matter what.

I do not know of a tool which will repair missing lump errors when the map was done in UDMF.

However, If the map was done in original DOOM format (ODF) or G/ZDoom in Hexen format (DiHF) then you can use Deepsea to restore the map with the missing lumps. In most cases that will work.

As to the nodes errors, I would delete the nodes lumps. Then use a proper nodebuilder (ZokumBSP or ZDBSP) to establish the nodes, or simply let GZDoom build the nodes at runtime, when there are none.

The wad I've been working with is one I first released 13 years ago, and I recently remembered using GLBSP to build the nodes at the time. I used it again and the issue seems to have gone away.