Frank
In case of changing weather it's possible to change the tyres on the grid. For it to work you have to enable advanced strategy and to use a dry tyre you must set one for your first stint in your strategy (and rely on advanced strategy to set you on Inters or Wets for Qualification in case its in the wet).
As it's not a bug I move this thread to Help&Support.
Frank, but how is it working to change the tyre? Our last race at Canada the weather changed after a wet qualy and even those managers who made the advanced strategy correctly couldn't change before the race. This was my case. I was using S as tyre compoun in my first stint and W over 3mm and also W after some laps without rain. My qualy has been made with W tyre as expected but I had no chance to change it before the race since the rain stopped.
Few managers told that they were able to change tyres in the strategy screen (near chat) but no one has been sucessfull trying to change it at the "radio" as it was working before.
Some managers also had their tyre changed back to S automatically (maybe it was right as I'm not sure how they configurated the advanced strategy).
Below it is possible to see race link.
https://igpmanager.com/app/d=result&id=27892829&tab=race
I hope that we can have any announcement telling us how it should work equally to everyone. It changed a lot race resulsts because many managers had to stop after the first lap and others could race properly once that they were able to chance tyres before the start.