Flows that were generated after October 2020 can not be exported as a Logic App JSON Template. Meanwhile the Docs were updated with the reason for the Change Quote:
Export to Logic Apps is unavailable for Power Automate flows created after August 2020. In October 2020, Power Automate standardized new flow creation on the OpenAPI 2.0 protocol. New flows based on this protocol are incompatible with Logic Apps workflows, so exporting these flows to Logic Apps was disabled. Instead, you must manually create logic apps for these flows.