No Creative Mode

In a 1.14 save file after updating to 1.15 I swith to Creative mode but the game isn't in Creative Mode. I recive the confirmation that the default gamemode is now Creative but can't fly, see the full inventory etc.

Debug report says this if it has any relation to the issue?

[1215/141641.396:WARNING:dns_config_service_win.cc(669)] Failed to read DnsConfig.