Looped directory dei font

Nell’aggiornare la cache dei font, ho un output di questo tipo:
`/usr/local/texlive/2019/texmf-dist/fonts/type1/vntex/cmbrightvn: caching, new cache contents: 11 fonts, 0 dirs
/usr/local/texlive/2019/texmf-dist/fonts/type1/vntex/concretevn: caching, new cache contents: 4 fonts, 0 dirs
/usr/local/texlive/2019/texmf-dist/fonts/type1/vntex/grotesqvn: caching, new cache contents: 1 fonts, 0 dirs
/usr/local/texlive/2019/texmf-dist/fonts/type1/vntex/txttvn: caching, new cache contents: 4 fonts, 0 dirs
/usr/local/texlive/2019/texmf-dist/fonts/type1/vntex/urwvn: caching, new cache contents: 30 fonts, 0 dirs
/usr/local/texlive/2019/texmf-dist/fonts/type1/vntex/vnr: caching, new cache contents: 55 fonts, 0 dirs
/usr/local/texlive/2019/texmf-dist/fonts/type1/vntex/vntopia: caching, new cache contents: 4 fonts, 0 dirs`
e tutto appare regolare, ma da un certo momento in poi ricevo:
`/usr/share/fonts/X11: skipping, looped directory detected
/usr/share/fonts/cMap: skipping, looped directory detected
/usr/share/fonts/cmap: skipping, looped directory detected
/usr/share/fonts/opentype: skipping, looped directory detected
/usr/share/fonts/truetype: skipping, looped directory detected
/usr/share/fonts/type1: skipping, looped directory detected
/usr/local/share/fonts/opentype: skipping, looped directory detected
/usr/local/share/fonts/truetype: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/adobe: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/arkandis: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/catharsis: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/gnome: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/google: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/gust: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/huerta: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/ibm: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/iginomarini: skipping, looped directory detected
/usr/local/texlive/2019/texmf-dist/fonts/opentype/impallari: skipping, looped directory detected`
Cercando con google, pare che questo non rappresenti un problema,
e infatti i font funzionano tutti. Ciò non toglie che non riesco a capire
da che cosa dipenda i fatto che alcune directory dei font son dette looped…

grazie
m