Well, if the chain crew isn’t there at the start of the half, it is attributable to them!
There are endless possibilities of potential problems (mechanical issues, unexpected/improbable injury, equipment failure, etc.). As part of the Officiating Crew, delaying the teams to set up, for the 2nd half kick off until EVERYONE NECESSARY was in their assigned positions, to actual determine what the problem and/or resulting delay might be, seems a far better practice than high lighting an inappropriate, unfortunate delay. The cause of the delay should be investigated, and dealt with,
AFTER the contest conclusion and addressed as deemed necessary.