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I'm trying to setup some data defined values in combinaison of point cluster renderer. In the example available in attachment, I've defined the non clustered symbol with a circle which use a data defined offset based on 2 fields folowing this expression : array_to_string(array("offx", "offy"))

In this example the defined expression has no effect however if I use some aggregate function : array_to_string(array(maximum("offx"), maximum("offy"))) it works while not clustered symbols does not need any aggregate and futhermore the resulting value become the same for each features (maximum of all features's values).

In the same way, trying to setup an offet for the cluster symbol using the maximum function seems to cumpute the maximum value of each feature instead of only the clustered ones.