פירוש על קידושין 47:1

Second tithe produce is usually redeemed, the money is brought to Jerusalem and used there to buy food products. The issue here is a woman redeeming her husband’s second tithe. When one redeems one’s own second tithe, one is liable to pay an added fifth. But when redeems someone else’s second tithe, one need not add the fifth.
According to the first opinion, that of the sages, the woman essentially is like her husband, and therefore she must add the fifth. According to R. Meir she need not add the extra fifth.

If the money and the tithe are her husband’s then all would agree that she is her husband’s agent and must add the fifth. And if it is her money (inherited), then all should agree that she is exempt from the tithe.
Therefore, the Talmud suggests that it must be a case where someone gives her money on condition that she use it to redeem the tithe. The rabbis hold that this money is automatically her husband’s and therefore, she is his agent and must add the fifth. R. Meir says it is not automatically her husband’s and therefore she need not add the fifth.
These opinions are opposite of those we saw above, and thus both seem to be contradictory.