Allow CL clients to parse future SystemConfig.ConfigUpdate events without critical error

[geoknee]

See this P/PS https://www.notion.so/oplabs/P-PS-Allow-CL-clients-to-parse-future-SystemConfig-ConfigUpdate-events-without-critical-error-269f153ee16280fe9c5eec1e7b6640aa?d=0a6f153ee1628275938583be004777b6