This error appears in the POSTING CONTROL DETAILS window when editing Requisitioner Id. 
 

Error while serializing contents.

This error happens when the server cannot serialize the data to be sent to the client.

A common cause is that one attribute's length exceeds the defined maxlength in the projection.

To find more info, open Log Window or Debug Console, refresh and then check Network Tab in DevTools. In the response there can be more detailed information about the exception.

Url: https://prod.***.local/main/ifsapplications/projection/v1/PostingControlDetailsHandling.svc/DynReference_RequisitionerLov?$filter=(startswith(RequisitionerId,%271%27))&$skip=0&$top=101

        Date = 2023-10-25T06:48:31.329Z

        Request Id = 46ffe212-6026-4278-b9c3-d2e9b2991699

        Client version = 22.1.3.20220602062839.0

<ERROR> {"error":{"code":"ODP_SERIALIZATION_ERROR","message":"Error while serializing contents.”</ERROR>

I checked all the tables and views related to this LOV to determine if there are any issues with its data type or maximum length. However, there was nothing wrong with that. This error occurs in a variety of scenarios, like when clicking the dropdown button, saving the changes and creating a new line in Posting Control Details. Sometimes it's getting saved without any errors. From what I noticed this only occurs for one type of posting. It's a bit confusing. Moreover, this environment isn't customized or configured.

I found some related questions on community, 

These references indicate that this may be a bug in 22R1. I need to confirm is this one is also the same bug or a different one.