The real question is how different is it from true nectar. They produce honey by preserving nectar in the first place. Of course even if they were given true nectar as a replacement directly (an ironic subversion of their job) it could theoretically cause issues from not being properly "preprocessed" or lacking the lead time to make a batch for their own consumption.
Just because sugar water isn't a good basis for humans doesn't neccessarily apply to bees - giving a cat a salad is not healthy for them and they will probably not be happy.
Honey contains lactic acid bacteria [1], which has proven to work as an antibiotic agent in scientific test[2]. Suger do not have that. Honey contains many other things, like pollen, that suger doesn’t.
Just because sugar water isn't a good basis for humans doesn't neccessarily apply to bees - giving a cat a salad is not healthy for them and they will probably not be happy.