It MIGHT have been that the system had brought the temp down where the temp wheel commanded it to be, so the system started cutting back to prevent it from being too cold. Remember it is an AUTOMATIC climate control system.
If you keep a thermometer in the vent and monitor it all the time, you will see many odd things while remaining comfortable. For me, this comes from monitoring vent temps on manual systems quite alot over the years. On those, turn it to max cool and it will just keep trying to cool until icicles drip off the vent. The ACC OTOH is supposed to keep it at the set temperature.
'88 300E 5 speed manual, 331K miles
"Change oil hot and change oil often"
“I'd like to know why well-educated idiots keep apologizing for lazy and complaining people who think the world owes them a living.” - John Wayne