Is Canopy 900 SM without antenna damaging?

Is it bad to start up a canopy 900 connectorized SM without an antenna on it ?

I regularly fire up the SMs in our office to upgrade the firmware and configure the units before our installers hit the road, and I do it without an antenna on it…

We haven’t been getting the performance out of the units that I desired, and now I saw a message like this subject on another board, and I’m starting to worry…

help!