if you keep asking about the same thing in a short space of time, it will start to throw completely different readings up which makes it more confusing. I try not to ask more once every 30 days unless something changes. So first possible cause is asking over and over. My personal readings deliberately start to throw up completely different scenarios! The lesson in this scenario is to trust the first reading, if we don't trust in what comes up, it will just become more and more confusing.
If you are spacing out the readings and getting very different readings, it probably means that things are changing. Just as an example think of the tarot like weather forecasting. Things suddenly change or there is so many variables! If you asking about predictive or long range type questions things might have completely changed since the first reading. You might have changed direction, other people involved too! Probably something has changed since the first reading or you have changed and gone in a different direction. We can override what comes up in the tarot because as humans we have free will.