I have an Environment with 32 servers and 2 packages.
After that I've added the 2 packages to all 32 servers and I've clicked on save button, at the page refresh the environment section was inaccesible and a red bar with error "500" appears.
Then I've restored the previous state using a DB (mysql) dump.
So I've tried again but now adding a package to one server per time and click the save button and the problem appears when I save the 15th server.
So it is necessary remove the last record inserted (relative of the 15th server) on KWDeploymentPackage table.
To work around the problem I've created 3 different Environment with 14, 14 and 4 servers respectively.
At the moment I don't know if the 2.2 version is affected by the same issue, I'll try to test on it as soon as possible.