Connection issues with a mountaintop node

"Hi
We have a mountain top node in the SF Bay area, running Rocket M5 & a 16dB 120 sector.
Need some help identifying possible causes.

It has been running well for a little over a year with very light traffic.
A few things happened all about the same time.  
1) we went from about 3-6 low level users (with no view of each other)
2) SNRs were about 20dB but the LQ & NLQ have degraded to <30%, often dropping all stations
3) upgraded firmware to 3.23.4.0

LQM was initially on, we then tried off, and now is back on again. (experimented with lower/higher min SNR & Quality)
Frequency: did a waterfall scan and noticed a slightly elevated noise floor on our channel.  Moved to a clear channel for a test and things seemed to recover. Then users moved and problem returned with users >3, and 1 who never successfully connects. Seems when users >3 things get worse.

But there are other symptoms.
1) The status screen shows "no rf connections"
2) the mesh status screen shows IP addresses for some of the users.
3) the neighbors status screen is usually empty
4) the live SNR charts show mostly of 0's & 95's along with some actual expected signal levels. (archives show 0's not 95's)
5) the "load average"  on the status screen will be close to or above 1.
6) going out to a portable location with a clear shot and >37dB signals, does not improve NLQ/LQ issues.

Jim 
N9JIM

Have lots of screenshots will only post this one showing archive chart, with station SNR & lots of "zeroes".
It seems to show the issue comes & goes over long or short periods.