~1100 hrs. local. 
Noticed LN2 boil-off vapor eminating from backside of CP1 dewar piping (i.e. not normal location) -> Investigation revealed the following: Indicated dewar head pressure @ 42 psi (nominal is < 20 psi).  The transfer line pressure relief valve was popped open and LN2 was being released onto the ground.  Found that the dewar pressure relief circuit was closed (manual valve was closed).  Also, the LLCV needle was fully closed even though CDS indicated needle was 20% open. -> I opened the deware pressure relief valve to vent the dewar head pressure through the economizer valve (i.e. returned to normal configuration).  I switched CP1 LLCV from PID to manual control @ 50% open and confirmed that LLCV would stroke open and closed with the instrument air valved in and out etc..  I then returned control back to PID and confirmed that the CDS output corresponding to 20% open really corresponds to the valve being 0% open.  

Conclusion:  The Praxair driver had likely closed the dewar head pressure relief (manual isolation valve) for some reason??? while filling on Tuesday and forgot to open it before leaving.  This would cause the head pressure to begin increasing.  The %open output of the CDS PID loop would then begin to ramp closed  Eventually, the LLCV would be closed.  Now the total pressure, head pressure + weight of liquid column, would increase until the transfer line pressure relief valve popped open.  It will take a day or two for the head pressure to get back to < 20 psi venting only through the economizer circuit.  The normal pump level swings will likely result due to the "warm" portion of the transfer line piping once the LLCV actually starts to open.