There probably isn't an issue but why take the chance. I pop the girls into a container and gently introduce water from the new tank. Even though we keep our tanks similar they are never 100% the same. There are temperature fluctuations, TDS in some tanks can rise due to population etc so while a small difference won't hurt any great difference can cause osmotic changes in the shrimp. PH is another issue - My tanks are all treated exactly the same , same water , same salty shrimp , same substrates but when testing ph there can be several points difference. Shrimp are very hardy usually so small differences don't cause much trouble but for the sake of a few minutes I don't consider it's worth the risk personally.
So far as far as I can tell I haven't ever had any females drop their eggs after transfer, I have had females drop eggs but not those in the maternity tanks.
But each to their own I guess. I will continue to take the bit of extra time to make sure my girls are OK