Hello Elena, thanks for the answer.
It might be that our project is from a previous version, but when we execute it on a functional test it works with no problems. Sadly we can't decrease the iterations of our testing, since we need to run our test with a thousand iterations and hopefully more. Unfortunately we tried using the alternative 'ReuseAppWindow feature' and it failed the same way as before.
Our test indeed has some custom code, but when we try it on a functional test it works pretty well.
The application is loaded, but the crash does happen randomly, sometimes at 200th iteration, 500th, etc. I shoul add that RAM and CPU never skipes at the moment of crash.
Thanks for your support, Elena.