Why is this an issue?

Cypress commands do not all treat callbacks in the same way. A callback passed to then runs only once when the preceding command resolves. If an assertion in that callback observes an intermediate state, it fails immediately even when the application would reach the expected state shortly afterward.

In contrast, Cypress retries a callback passed to should together with the preceding query until its assertions pass or the timeout expires. Assertions on asynchronous user-interface state should therefore use should so they benefit from Cypress retryability and do not make tests intermittently fail.

This rule targets then callbacks that only make assertions, optionally using local calculations. Keep then when the callback performs one-time side effects or transforms the yielded value, because retrying or replacing those operations could change the test’s behavior.

cy.get("[data-cy=status]").then(($status) => { // Noncompliant: assertions in "then" are not retried
  expect($status.text()).to.equal("Ready");
});

Replace then with should when the callback only computes values and asserts on them.

cy.get("[data-cy=status]").should(($status) => {
  expect($status.text()).to.equal("Ready");
});

Resources

Documentation

• Cypress Documentation - Retry-ability
• Cypress Documentation - then
• Cypress Documentation - should