Here is all I can tell you. I run SNOM’s at home 300’s and 370’s. In fact I bought the 370’s at a FreePBX auction after one of the training classes from Philippe.
I have some running v7 but most running v8 and I have no issue whatsoever with inbound caller ID on FreePBX since version 2.4.
I can dump my config tomorrow and take a picture to show you I am not nuts.