This is very peculiar behavior.
It's gone undetected for over a year and hopefully the KMAT will be retired.
We typically have a basic 1:1 KMAT:class relationship. Sometimes we will share a class and all is well, but we share more Characteristics. We inherited some KMAT and configurations a few years ago that were poorly maintained. 😔
With CL03 you can modify 1 Class. When analyzing a KMAT and its class I noticed the presentation of configuration in CU50 and VA01 wasn't what I was expecting from what I saw in CL03.
Upon digging deeper and looking at table KLAH I noticed this Class has two IntClassNo entries. Ruh-roh.
Notice specifically that the Class name is the same on both records.
This relates to unique sets of characteristics in KSML.
The problem is as a user you can only go to CL03 and specify the Class name to change. When you do this SAP chooses the lowest IntClassNo (1712 in this case) so you will only see those Characteristics that relate.
Both KMATs have the same class name assigned in CU43, but within CU43 you can see they are using different Characteristics.
The main difference between the two is the shared Characteristic TPEM_5AC. I don't know how to add this to the IntClassNo 1727 because CL03 will only change 1712.
I am not sure how this happened, but it will possibly present a challenge if the KMAT that relates to the other IntClassNo needs a unique characteristic. I'm a little stumped on two fronts. 1 - how did this happen and 2 - how can we modify Class PC35MR_3 that relates to IntClassNo 1727?
Across hundreds of Classes and KMATs this is the first time I have seen this happen.
Hopefully someone in the community has been more fortunate.
I'd just like to know how to solve this, and even prevent it. :/
Note if you use PMEVC for KMAT A and KMAT B it's easier to visualize the differences between the Class because it is relating the IntClassNo, but PMEVC is not permitting adding a Characteristic (separate post).