wow it seems working now. I suppect a conflict with Duplicate Post extension.
I tried to add my new events for our new season and I used Duplicate Post to “duplicate” events of last year. Those event was in trouble.
If I use “new draft” and not “duplicate”, I get my Google Map on the venue page! If I add a new event that is OK too!
The only remaining question is why that didnt work when I added event (without using Duplicate Post) 5 days ago? Well I still dont know.
We can close the issue. Thanks for your help.