I found the following Statement on the German Wikipedia page about the A320 family of aircrafts.
Nach erheblichen Schwierigkeiten in den Anfangsjahren erreicht die A320-Familie mittlerweile eine Abflugzuverlässigkeit von 99,7 Prozent. (https://de.wikipedia.org/wiki/Airbus-A320-Familie#Wirtschaftliche_Aspekte)
This roughly translates to:
After significant difficulties in its early years, the A320-family reaches a Dispatch Reliability of 99.7% nowadays.
I could not find more information about this statement, so my question would be why the Dispatch Reliability of said aircraft family was supposedly significantly lower in its early years? Is it normal for completely new types of aircraft to have such a low DR that it's worth mentioning?