This bug has been reproduced in Indesign 15.0 and 18.5. MacOS Sonoma.

When you convert a BLACK text to outline, Overprint Fill is automatically enabled in the Attributes panel. The ‘Overprint’ selection remains applied even if you change the colour of this object.

I've just had a print advert blown out of the water by my client because half of his logo had disappeared. It was blue and was overprinted even though I hadn't set anything like that.

It came about in the way described above: a text was converted into paths, the resulting logo was recoloured in blue - but it remained an object for Indesign to print over.