Sometimes the country made a deal to export a certain quantity of something by a certain date, but in the meantime domestic demand rose, so they have to fill the deal with exports, and import to cover what the locals are buying.

Sometimes, through a series of financial jiggery-pokery well beyond ELI5, it's profitable. Other times, there are differences that just don't show up in general statistics.

For example, the US both imports and exports crude oil. This looks crazy. BUT... the US refining industry is set up to refine the specific kind of oil they import, which is low in sulfur, and exports the local high-sulfur oil to places where they have a refining industry equipped to deal with that already in place. But why, I hear you ask, not refine local oil locally? It's more cost-effective to swap oils around than rebuild refineries.

Or another country might be importing and exporting "alcohol", which also looks crazy... but if one is high-quality alcoholic beverages and the other industrial-grade solvents... not so much.