Out of my depth here but the log pointed me to line 1135 of WebCoRE Piston where I changed runIn(t, timeHandler, [data: next]) to runIn(toInteger(t), timeHandler, [data: next])
The piston never appeared to do anything, but something actually got scheduled for the appropriate time, and the error message got quite a bit shorter, to wit:
An error has occurred while subscribing: groovy.lang.MissingMethodException: No signature of method: app15196121587141013158970.toInteger() is applicable for argument types: (java.math.BigDecimal) values: [13.747]
The resulting log showed:
2018-02-25 21:33:46.264:info╔ Piston successfully started (426ms)
app:2692018-02-25 21:33:46.262:error║ An error has occurred while subscribing:
app:2692018-02-25 21:33:46.255:info║ Setting up scheduled job for Sun, Feb 25 2018 @ 9:34:00 PM EST (in 13.747s)
This time no line number was logged and I see no other places in the code where this change could apply. Edit: changing piston trigger time conditions from ‘at’ to specify a condition including ‘between two times’ executes but still throws the error and gives the line number of the modified line.