Technique F1: Failure of Success Criterion 1.3.2 due to changing the meaning of content by positioning information with CSS:

Remove the style information from the document or turn off use of style sheets in the user agent.

If I turn off CSS, this can have undesirable side effects, such as display:none content being shown or CSS-generated content being hidden, which has nothing to do with the F1 technique, but can still lead to incorrect test results. I therefore suggest changing the test procedure. Instead of turning off CSS, the reading order should be tested with CSS, e.g. with a screen reader or in the Dev Tools, Accessibility tab (i.e. checking the accessibility tree)