Why villager-farmer plants unrelated crops?

Solution 1:

This is probably because the villager has wheat and beetroot seeds in his inventory. There are a few ways to solve this.

  1. Mine the false crops instead so he cant get the seeds. The villager will then plant the seeds in the empty farmland and if you continue this act he will eventually run out.

  2. If that doesn't work or if you don't have the time to do so kill the villager and get a new one.

Hope this helped!