issue with migrate delph 11 iw15 to delph 13.2 iw 16.2.6

[PDSBILL]

Delphi 13.2 / IntraWeb 16.2.6 ISAPI, migrated from Delphi 11 / IW15. A custom TContentBase handler accepts GET. POST reaches OnExecuteRequest and its form fields parse correctly, but with RequiresSession=True, neither OnBrowserCheck, OnNewSession nor Execute runs; response is 404. With RequiresSession=False, Execute runs with a nil session. CanStartSession=True; RequiresSessionStart=False. The API must support an initial POST without a preceding GET.