Is it OK to wash baby bottles used exclusively for breast milk in fleishig dishwasher with fleishig dishes? What about hand wash with hot water in fleishig sink with fleishig dishes?
Technically it is permitted, but it is a very bad habit to get into, because eventually you will end up putting the real milky bottles into the fleishig dishwasher and wash them with hot fleishig dishes. A proper kosher kitchen should be set up that such bottles, even though they are not milchig, should stay on the milchig side.
It is permitted because there is no issur bring done here, as the bottles are pareve. It is also not maris ayin, because there is no issur being done even by washing milchig and fleishig, it might make them trief but it isn’t an issur that we should say that it is maris ayin.