rear its (ugly) head
US /rɪər ɪts (ˈʌɡli) hɛd/
UK /rɪər ɪts (ˈʌɡli) hɛd/

1.
reaparecer, dar as caras
if an unpleasant situation or problem rears its head, it appears or occurs, especially after being hidden or dormant for a period
:
•
The old rivalry between the two teams began to rear its ugly head again.
A antiga rivalidade entre as duas equipes começou a reaparecer.
•
Whenever we discuss money, his true colors rear their ugly head.
Sempre que discutimos dinheiro, suas verdadeiras cores aparecem.