AD8034 Peak Detect clipping/clamping

I have implemented the Peak Detect in Fig 55 on pg 19 of the AD8033/8034 data sheet.  We have hand assembled 3 boards.  2 of the PCBs work fine, but one board is clipping/clamping.  At the output of D1, it clamps at 4V.  At node 2, it clamps at 3V, and at node 3, it clamps at 2V.   (Vout is also at 2V)  Since 2 boards work fine, I assume there is not a fundamental design flaw.  Below are a few details:

+Vs = 12V  (checked with meter)

-Vs = -12V  (checked with meter)

1 ohm resisters in supply path.  Current is a couple of mA

replaced all passives, including D1, D2, D3. 

removed and shorted diodes, just to see if they were culprit.

Any ideas to try?  (Note:  we will start assembling PCB #4.)

Thanks