Outgoing Calls only works with 10 digit dial - Skype for Business

[jvoros]

T48G with firmware 35.8.0.70 connected to a Hybrid deployment of Skype for Business (0365 and Lync 2013 on Prem) with Cisco UC acting as the PBX on prem to SIP trunks.

We are unable to make Outbound calls from the device unless we use full e.164 dialing. For example +1 212-555-1212
All other calls end in a busy signal and 'call failed' error. You must use the +

What works:
Skype to Skype Calls - Inbound / Outbound as chosen from addressbook
Inbound Voice calls (i.e. someone calls the xxx-xxx-xxxx number)
Outgoing calls if +1xxx-xxx-xxxx

What doesn't work:
Four digit dial. we use 4 digit extensions in the office. example 1212
Our cisco is configured to dial 9 for external calls so 9-1-212-555-1212. This does not work
1-212-555-1212 also doesn't work

Connected as the same user account in SfB:
When using our Skype soft client (on a notebook) all of these work
When using a Polycom VVX600 connected through SfB, all of these work

The polycom is configured the same way as the Yealink and it works.

Neither device has the concept of dial plans that let you do replacements on the device themselves. The yealink only has Dial Now which is more like a quick dial feature than a replacement feature. There doesn't appear to be any settings for e.164 or the ability to recognize short extensions. SfB doesn't have these settings in it. Still need to investigate cisco but the fact that the polycom works makes me think its the phone settings and less the server side.