Invalid stops is a broker response to the attempted stop. Brokers have minimum stop levels that vary.
For this and other reasons, we have copy limits set off by default.
You technically don't need it as your master stopping out on its limit, will create a close event on the slave regardless of their limits.
You are free to choose to copy them but you will get odd scenarios through copying them. You can read about the stop and limit settings in the knowledge base under trade copiers.
To enable/disable Copy Stop Loss & Take Profit go to Configurator > Trade Copier > Copier Configuration > Stops & Limits > Then enable/disable Copy Stop Loss & Take Profit.