Is it normal for eyes to, on occasion, have irregular size pupils? For example, one being small and the other being quite large in comparison, but then stabilize to normal size again?
This does sound unusual and is worth investigating. I would arrange an appointment with your optician to carry out come further tests.
There are signs that your optician will need to look out for such as the position of your eyelids, your vision, and visual field and how well your pupils react to light and near objects. Any change in pupil size and shape should be investigated as soon as possible.