Hello Bharani,
thank you for the answer. Looks like we are moving towards the source of the error, however, AFAIK the user of the Adwords API doesn't create the platforms attached to a campaign but they are created by default for each campaign. We were only aware of the existence of devices (Desktop, Mobile Highend and Tablet) and thus we only modify them as you can see in the logs. This CI test pipeline has been working for 1 complete year now but it started failing last 24th of April due to the experiments failure only when there are platforms modifiers previously set. I have attached 2 screenshots of the logs where you can see in our Adwords CI account with more activity when exactly we started to see the problem (5:38 pm of the 24th), just 30 seconds earlier we were creating campaigns as always with only 3 platforms, but I would like to insist, this isn't something we can configure through the API and thus, there isn't anything explicitly related in the API call to create the campaign.
I can also add that we have 5 adwords test accounts and all of them are affected by the issue consistently.
With this evidence I would like to suggest that the process of creating an experiment is somehow incorrectly trying to clone a modifier (30004) that we haven't created/modified and even worst, it looks like it doesn't exist anymore.
Please let me know how this progresses or if we can be of any help, we are very much interested on a solution.
Thanks,
Yeray