I was experimenting with building a Way of the Kensei monk to level 20, and discovered a bug. Each level where you add a new kensei weapon (6th, 11th, and 17th), the kensei weapon feature in your character sheet only shows the latest addition to your list, even though it shows that you can have up to 5 kensei weapons. Here is the link to my character where you can see this bug. Note that this bug only appears to affect which weapons are shown as kensei weapons. I still am given proficiency with all the weapons I chose, and the martial arts die is given as their damage under the actions tab.

Edit: Fixed the link.

Edit 2: Link broken again as I accidentally deleted the character.

Bump to this. It does seem to be a display error only as the chosen weapons are treated appropriately on the 'Actions' section of character sheet. For reference, here's a copy of a Kensei monk I created. (https://ddb.ac/characters/38511059/j0ksPU). As you can see listed under Features, the weapons chosen at 6th and 11th levels aren't reflected. The weapons chosen initially at level 3 and then at 17 are, however.