Solved

Can't change wet tyres on grid on phone

What did you try to do?
Qualified on inters it was raining got to grid trued changung tyres to wets but it wont change. Others changed tyres on pc but on app you can't change tyres on grid.

What happened instead?
Can't change tyres

Did the problem happen while using wi-fi, mobile data, or both?
Both

Did the bug happen in the app, on PC, or both?
App

What is the model of your device?
Android

What is the operating system?
Android

What is the version number of the operating system?
Android

Can the bug be reproduced?
Yes

Additional comments:
Could have scored a 1-2 instead got no points and race ruined 

I got it to work without advanced strategy. Go to the strategy button on the top of the screen and go to stint 1 and click on the tires you want.

Advance set up was enabled main setup soft tyre of raining over 0mm advance to Inter tyre. I did qualified on Inter so before race starts why couldn't I change it to wets? 

Were you in quick strat tab at bottom or main strat tab at top? I can change it on mobile, but only from the main (top) strategy tab, in stint 1

Quick strategy tab at the bottom of app. 

Yeah I can only change from the top :/

Yesterday again we had rain I did soft for original tyre wet for advance set up but this time I had wet tyre as water was 3.4mm I did gat wet tyre. Went to grid before race start tried to change tyre from bottom control no change tried top control still no change. Game gave options to go to soft Inter wets but when selecting any of those no change in current tyre. Same as it was yesterday when I qualified on Inter tyre.

Hmm ??

Did you go back to stint 1? I'm pretty sure igp automatically shows stint 2 to you.

Didn't know about that so not tried or paid attention to that will have to wait for another rain race now. 

I believe i will have a wet race so i will try it out for you as i play on mobile as well!

I can confirm that it works!