The effect of bubble tea only doubles the bonus mood and energy gained from completing meditation, not the per-second amount. For example, with meditation rank 1, if you meditate for 4 seconds you would normally receive 7 mood/energy, 4 for the 4 seconds plus 3 for completing your meditation. With bubble tea you should receive 14 but you only receive 10. It doubles the bonus 3, but does not double the 4. This happens at all rank of meditation.
Focused meditation and transcendental radiation both work correctly with bubble tea, only normal meditation has this problem.