Flow Logging getting No enum value found called true

[pinoybug]

Hi,
I have a flow that tries to log the following:
FLOWLOGENTRY (APEX): Log Save New Contact
Inputs:
faultMessage = {!$Flow.FaultMessage} (This error occurred when the flow tried to create records: DUPLICATES_DETECTED: You're creating a duplicate record. We recommend you use an existing record instead.. You can look up ExceptionCode values in the SOAP API Developer Guide.)
flowName = {!flowName} (Account_Contact_New)
loggingLevelName = ERROR
message = Error Saving New Contact
saveLog = true
saveMethodName = true
tagsString = Ad Contact New, Save New Contact

But I am getting the error: No enum value found called true

I saw a similar question but it had no resolution

[pinoybug]

It happens even if I set Save Log = {!$GlobalConstant.True}

[pinoybug]

Update: this only happens in sandboxes and not prod.