The console seems to terminate the command line by itself when trying to make a channel selection.
Explanation of Issue
One reason for this might a physical encoder or level wheel continuously delivering input.
It is expected behavior to terminate the channel selection (and therefor the command line) when moving an encoder or the level wheel after entering a (Channel) number. However, if one of the encoders or the level wheel is delivering continuous input because of a technical fault, the command line is probably terminated too early.
In most cases, this can be resolved by rebooting the console. If the problem persists, a technical problem with a physical element of your console might have occurred requiring help by ETC Technical Support.