This is my flow:
On a previous step, the "Tasks" variable is initalized as an empty array.

Now, after getting all the stuff from Planner, I apply 2 filters and I want it assigned to the "Tasks" variable.
This all seems very logical, but I get the error:
BadRequest. The value '[{"@odata.etag":"W/\"JzEtVGFzayAgQEBAQEBAQEBAQEBAQEBASCc=\"","planId":"johCFoq4nEyhOcbgjLkzN5YAFYWU","bucketId":"uoRC3WMr70WkaUCOGWZ69JYAJEHv","title":"Reception, validation and account of local suppliers invoices","orderHint":"8585957052767015463","assigneePriority":"8585957052767015463","percentComplete":0,"createdDateTime":"2020-11-20T19:46:48.7760344Z","dueDateTime":"2020-11-20T10:00:00Z","hasDescription":false,"previewType":"automatic","referenceCount":0,"checklistItemCount":0,"activeChecklistItemCount":0,"id":"bjCAp0IHFkyrLFrIRVFEDJYAFeHg","createdBy":{"user":{"id":"25e6bf64-416e-45c2-8350-9f747027d3c5"}},"appliedCategories":{},"assignments":{"25e6bf64-416e-45c2-8350-9f747027d3c5":{"@odata.type":"#microsoft.graph.plannerAssignment","assignedDateTime":"2020-11-20T19:46:48.7760344Z","orderHint":"8585957053367796571P2","assignedBy":{"user":{"displayName":null,"id":"25e6bf64-416e-45c2-8350-9f747027d3c5"}}}},"_assignments":[{"userId":"25e6bf64-416e-45c2-8350-9f747027d3c5","value":{"@odata.type":"#microsoft.graph.plannerAssignment","assignedDateTime":"2020-11-20T19:46:48.7760344Z","orderHint":"8585957053367796571P2","assignedBy":{"user":{"id":"25e6bf64-416e-45c2-8350-9f747027d3c5"}}}}]},{"@odata.etag":"W/\"JzEtVGFzayAgQEBAQEBAQEBAQEBAQEBASCc=\"","planId":"johCFoq4nEyhOcbgjLkzN5YAFYWU","bucketId":"4VBW8a5Yq0S_ANzJDVptm5YAFqWM","title":"Data maintenance of master & controle files in MFG-PRO","orderHint":"8585957052771171382","assigneePriority":"8585957052771171382","percentComplete":0,"createdDateTime":"2020-11-20T19:46:48.3604425Z","dueDateTime":"2020-11-20T10:00:00Z","hasDescription":false,"previewType":"automatic","referenceCount":0,"checklistItemCount":0,"activeChecklistItemCount":0,"id":"qiu6A-ZpGkydhZeuGMWw7pYAC-2e","createdBy":{"user":{"id":"25e6bf64-416e-45c2-8350-9f747027d3c5"}},"appliedCategories":{},"assignments":{"25e6bf64-416e-45c2-8350-9f747027d3c5":{"@odata.type":"#microsoft.graph.plannerAssignment","assignedDateTime":"2020-11-20T19:46:48.3604425Z","orderHint":"8585957053372264963P*","assignedBy":{"user":{"displayName":null,"id":"25e6bf64-416e-45c2-8350-9f747027d3c5"}}}},"_assignments":[{"userId":"25e6bf64-416e-45c2-8350-9f747027d3c5","value":{"@odata.type":"#microsoft.graph.plannerAssignment","assignedDateTime":"2020-11-20T19:46:48.3604425Z","orderHint":"8585957053372264963P*","assignedBy":{"user":{"id":"25e6bf64-416e-45c2-8350-9f747027d3c5"}}}}]}]' of type 'Array' cannot be appended to the variable 'Tasks' of type 'Array'. The action type 'AppendToArrayVariable' only supports values of types 'Float, Integer, String, Boolean, Object'.