Missed a pentest finding

Have you ever missed a pentest finding and the client found it later on and escalated it to the management (the security services company you're working for) , if yes how do you deal with it? Also is it normal to miss a finding even if you've been pentesting for years? Please share your experience because my impostor syndrome is getting the best of me rn.

client cybersecurity deal experience found management normal pentest pentesting security security services services share working yes