All tests ok in cypress.open, but when using cypress.run if 1 test fails, all subsequent tests fail

[andrewwhiteart]

i have testIsolation: false. cypress 13.3
I am using salesforce, i login fine in my before hook then i navigate to the page under test.
Then i have tests for each field on the page, i have left two in the example provided but there are about 30 tests.
If i run this and all 30 tests pass - all is well in both cypress run and open.
But if any test fails, cypress open handles this (only that test fails)
Where as with cypress run once a failure is encountered EVERY subsequent test fails.

It appears as though each subsequent test after a failed test no longer has access to the DOM, the error provided is this:
TypeError: Timed out retrying after 4000ms: Cannot read properties of undefined (reading 'length')
and if i change one of the subsequent tests to simply locate something on the page which is always present, it cannot find it.

I am totally stuck, any help is much appreciated

    before("Login", function() {
        Cypress.session.clearAllSavedSessions()
        cy.loginIntoSF("underwriter")
        cy.search_for_id_and_select_case_form('276345725')
    })

    describe('Check Salesforce > Case form > Other Applicant', function() {

        it("Details > applicant > Account Name", function () {
            cy.get(`[field-label="Account Name"]`)
                .should('be.visible')
                .contains('Ivor Dewdney')
        })

        it("Details > applicant > App Member", function () {
            cy.get(`[field-label="App Member"]`)
                .should('be.visible')
                .contains('Ivor Dewdney')
        })
    })
})