Cisco VoIP Handsets Un-Register After Settings Change

[jwwork]

I have a stack of 4 MS425's at the core of my network doing all my layer 3 routing.  At the edge I have a mix of mostly traditional Cisco switches with some MS350's starting to get mixed in.  We have a Cisco VoIP system that we host on-prem.  The other day I had to create some additional layer 3 interfaces on the core stack and I noticed that while doing this, all of our VoIP handsets drop their connection to call manger (display goes blank for a couple seconds, phone shows "registering" then comes back to life).  We are running 9.36 on all of the Meraki switches.  Any ideas what is going on here?

[Adam]

I've definitely noticed that when adding layer 3 interfaces to a stack the other switches have to sync the config. But I haven't noticed the interruption. Is the L3 stuff you are working on in the same subnets as your phone/voice VLANs or completely separate?

[jwwork]

These are completely different subnets.  This is happening when I create a new subnets I was working on for an upcoming wireless project.  I didn't modify the subnets that any of our VoIP stuff is in.

[PhilipDAth]

The 9.x code does a few funny things.  I would suggest going to 10.26.