POSTGIS Datasource + Cluster throws error

[Revo2022]

Expected behavior and actual behavior.

I have a layer with a postgis data source. If I also enable Clustering, the following error is thrown:

error on line 66 at column 40: Specification mandates value for attribute x

• The mapfile runs fine in version 7 and 6

Steps to reproduce the problem.

• Basic getcapabilities request

Attach simple test case (drag/drop it here)

• Use cluster documentation example code and replace data source with your own postgis point layer, eg. using the following code

CONNECTIONTYPE postgis
CONNECTION "xxx"
DATA "geom from tbl_kita USING UNIQUE id USING SRID=25832"

Operating system

Debian 10

MapServer version and installation method

Version 8.0.0