I have experience that randomly a conditional task get executed twice in a build without changing any configurations.
When it get executed twice it says that 'unfulfilled condition' for the first attempt and second time with success.
The issue is when that happens build will fail without any other reason.
The logs says :
Skipping task 'Checkout Default Repository' because of unfulfilled condition. Reason: Variable planRepository.1.branchName equals master
All conditions for task 'Checkout Default Repository' were met. Conditions: Variable planRepository.1.branchName equals master