Yes, I have noticed this on some occasions. I recently did a session where I sent the vocalist one of the two mics she was recording on to monitor in her headphones. This mic was completely unprocessed- no eq, no compression. I found she was able to stay in pitch and follow herself better.
I feel that the very slight variances in amplitude and tone that compression brings can subconsciously affect a singer's performance if he/she is sensitive to that. It really informs you that people can be very responsive to subtleties and that every single element in the monitoring and recording chain matters.
Thank you Micheal!
I wondered if I was the only one experiencing this...
One singer I work with a lot is very sensitive to this. She really likes having both the compressed and dry vocal in her cans (kinda parallel compression) so the quiet passages are brought up, but when she really wails she doesn't feel crushed.