Not entirely sure where you got that but I can tell you it certainly isn't true.
If he was that monstrous to work with, I seriously doubt that David Zippel or Glenn Slater (who can more than hold their own) would be offering their services to work with him a second time.
As far as Tim Rice, the greater part of their arguments had nothing to do with what happened during their previous collaborations. The first major rift with Andrew was a rejection of a lyric he wrote for Memory and how that rejection was managed (made all the more awkward by the fact that Tim's mistress, Elaine Paige, was trying to get the song and lyrics right during previews for CATS). Tim still had Andrew in mind when he wanted to write CHESS but Andrew was not at all interested in the subject matter.
Since then they have simply gone their seperate ways with other collaborators.
Tim Rice has voiced his opinion that, as older adults, he doubts they would collaborate as well as they did when they were younger. He once quoted “We had a great 10 years. Very few artistic partnerships last more than 10 years, and if they do they tend to go down the tubes."