Transaction Group and Run Always Expression

This problem started today. I have a transaction group that is suppose to run every minute.

It has 3 items:
Line#Counter = OPC to counter in PLC

Line#Previous = Run always script

SELECT Line1Current
FROM LineRates
ORDER BY linerates_ndx DESC LIMIT 1

Line#Count = Triggered Expression


For some reason every other cycle it is not updating the previous count and the difference for one minute is actually 2 minutes.

Any ideas as to where to troubleshoot this?