I am new at PsychoPy (Builder), but probably any advice or suggestion could help to solve your problem.
Just in case… have you checked that the units in the text object did not change? Specially: letter heigh and position.
Check the units in the Experiment Settings window: the same value in norms or pixels units may present or not the text in the screen (either for the size of the letters or the position in the screen).
If this doesn´t work, please comment other important details from your experiment.