Why is lpm_add_sub greyed out in the IP library for Max 10 devices?

Hi, I installed all devices. Then I right-clicked in the .bdf window, selected "insert symbol", and got following dialog:

Then I looked in the IP catalog:

I had previously imported an instance of lpm_add_sub from an earlier project made under quartus prime 15.1:

When I double-clicked this symbol, I got the wizard dialog:

The device assignment is 10M08SAU169C8G, although I have tried with several different MAX 10 devices, always with the same result. When I try the same with a Cyclone 10 device, the lpm_add_sub reappears:

I have a workaround (by importing an instance of lpm_add_sub as project ip) but it would be great if I could use it directly.

Thanks,

Joe