Reverb not working when moving from 4.25.4 to 4.26

Hi there , I’ve gone back to basics using the 3rd person template but still can’t get it working.
Importing a working reverb basic setup from 4.25.4 doesn’t work in 4.26.
Also with the reverb debug on ; dropping a reverb effect into world settings shows an active reverb in 4.25.4 but none in 4.26
is there something I’m missing.? I don’t understand why the engine isn’t even seeing the world setting reverb effect.
Thanks !