Much has been made of Bea's belief she was more of the star and her rumored bitterness over Betty and Rue winning the Lead Actress Emmy before she did.

Is there any record of how she reacted to being snubbed for the last 3 years of the show?

Not that I've heard, and I've read both of Betty's memoirs, and Rue's memoir. In Betty's, she points out that Bea didn't even congratulate her the day after she won the Emmy award.

Betty White was sweet and good natured, feminine and pretty, and had a normal female voice. Everything Bea couldn't be. Seems obvious there was some major jealousy/resentment going on there.