If "pegging meters" means they're continuously lit up to the red, I've experienced such in the past, too.
Unfortunately I don't remember the details, but it was about routing/souncard settings. In my case the pegging was due to an audio feedback loop, which just did not come out from the loudspeakers. The mobo sound card had something to do with it.

i used to get a similar problem that after much testing, i found out it was being caused by the VX-64 Vocal Strip.  but that was back in either X2 or X3 days.  the plugin no longer causes me any problems.

At this point, I'd install CbB. I have both installed, using CbB. they've made many bug fixes, perhaps it will help… 

I spent an hour dealing with that yesterday. It was happening on only one project, but a project I'd had open earlier in the day without issues and had not changed.
 
The symptom was two pops, then silence, and +9 dB on one of the sub-busses (and master). Changing the buffer size did alter the symptoms a little: the smaller the buffer, the shorter the interval between the pops.
 
As was the case the last time I saw this (maybe 1-2 years ago), globally bypassing all fx bins made the out-of-control signal settle down. And as before, re-enabling them one at a time resulted in the problem going away. Once gone, it stays gone, even after closing and re-opening the project. I'd made no modifications, had not closed any programs, nor rebooted before or after the problem showed up. Today it opens just fine.
 
Cosmic rays. Must be.
 

Where I have seen this was always related to something in the Pro-channel.  In my case it was usually the console emulators. If I disabled it it would go away. However, If I re-enabled it it would come back.  If I deleted the offending Pro-channel plug-in and re-added it it would go away for good.

Thanks for the replies!

About the drivers, I don´t believe the issue is related to the soundcard as the issue will even affect audio exports. According to Noel, it´s a NaN being generated somewhere whithin the VST signal flow.
 
I´m using a Nvidia GTX 1070, HDMI HD audio driver is disabled.
 
64 bit processing does not seem to make a difference. It also seems that disabling hyperthreading makes the problem show up less frequently but again, it could be random.

I disabled core parking by using Bitsum Park Control, it did seem to make the problem appear less frequently but it´s hard to be sure.
 
I´m not seeing this issue on all projects, only older ones. I´m wondering if this is because they were created using an older Sonar version or because they have become more cluttered?
 
Edit: I´m also leaning to blame cosmic rays for this odd issue. Perhaps the intermittent nature of the problem is due to sun storms :) ?