Chromebooks drop calls after 5 minutes with 24101 Method not allowed

Question

So I work for a company that runs Skype for Business 2015 and we recently rolled out chromebooks and the users are getting dropped calls after 5 minutes almost like clockwork.

Here is the error:
24101; Component="RTCC/6.0.0.0_UCWA/6.0.0.0 AndroidLync/6.28.0.15 (Acer Chromebook R13 (CB5-312T) Android 9)"; Reason="Local additional diagnostics information"; exceptionmessage="A 405 (Method Not Allowed) response was received from the network and the operation failed. See the exception details for more information."; CallSignalingSessionPurpose; CallState="Established"; CallStyle="None"; Source=""

I just installed the most recent cumulative updates like an hour ago. Tested it and the same thing. Most of my searches told me an update would fix or setting this for the trunk:
Set-CsTrunkConfiguration -Identity "PstnGateway" -EnableSessionTimer $false -RTCPActiveCalls $false

But it is still happening. I would appreciate any guidance or paths I should take. If this isn't enough enough please say so.