I'm not sure this was reported a few months ago. I searched for the issue using keywords K22 FTM Input Capture and did not see it, so I'm reporting it here.
The 2.3.1 SDK supplied for this family of MCUs listed below has a bug in the FTM2 Input Capture driver.
Attached is a complete SDK project with the documented error.
The issue on the K22s listed below is there are two AIPS areas. AIPS0 and AIPS1. The FTM2 base exists on BOTH AIPS areas. The SDK code uses AIPS0 in one section and AIPS1 in another section, thus FTM2 never works properly.
Hope you find this useful.
I want to acknowledge Benjamin Tait for doing the detailed investigation on this problem.