What steps will reproduce the problem?

Write 2 instances for same type and class in 2 different modules, then import this modules in a 3rd one (and redefine the instance again)

What is the expected output? What do you see instead?

It is not really clear what should be expected. Certainly, a warning is the least one would expect.

It looks like it just sticks with the first instance it sees and ignores the others. It should warn about duplicate instances and reject definition of a third one. It should also select the last instance it sees, in accordance with the behavior on name clashes.

Please use labels and text to provide additional information.

chpatermodules.tex has a todo entry for this. Document when fixed.

Fixed and documented with r204 The last imported instance will be used, for all others, a warning message will be emitted.