Expression evaluation error at function a!forEach: Cannot compare incompatible operands of type Date with Timezone and type Null.

We have the code below which is encountering “Expression evaluation error at function a!forEach [line 12]: Error in a!forEach() expression during iteration 25: Expression evaluation error : Cannot compare incompatible operands of type Date with Timezone and type Null.”

/*if(*/
/*exact(ri!clientPlanner.segment, cons!CAS_SEGMENT_LARGE),*/
/*{*/
with(
/*backdate is first day of open accounting month*/
local!backDate: rule!CAS_firstDayofAccountingMonthByDate(date: today()),
local!months: rule!CAS_calculateNumberOfMonths(ri!policyEffectiveDate, ri!expirationDate),
local!currency: "USD",
local!annualAmount: ri!annualPremium*(ri!commissionPercent/100)*local!months/12
,
/*transaction for each month of the policy*/
a!forEach(
items: enumerate(local!months),
expression: with(
local!firstMonth: month(ri!policyEffectiveDate),
/*the next month will be the first month + index*/
local!monthPlus1: local!firstMonth+fv!item,
/*gets actual next month*/
local!nextMonth: if(
local!monthPlus1>12,
local!monthPlus1-12,
local!monthPlus1
),
/*gets year for the next month*/
local!yearForNextMonth: if(
local!monthPlus1>12,
year(ri!policyEffectiveDate)+1,
year(ri!policyEffectiveDate)
),
/*for first item, transaction date is policy effective date. for all others, first of month*/
local!expectedTransDate: if(
fv!index=1,
ri!policyEffectiveDate,
date(local!yearForNextMonth, local!nextMonth, 1)
),
/*back date if already passed the closing day*/
local!accountingDate: if(
today()>rule!CAS_getLastAccountingDayOfMonthByDate(compareDate: local!expectedTransDate),
local!backDate,
if(
today()>local!expectedTransDate,
if(
month(today())=month(rule!CAS_getLastAccountingDayOfMonthByDate(compareDate: local!expectedTransDate)),
local!expectedTransDate+daysinmonth(month(local!expectedTransDate), year(local!expectedTransDate))-1,
today()

),
local!expectedTransDate
)
),
local!amount: if(
fv!index<local!months,
round(local!annualAmount/local!months),
sum(
round(local!annualAmount,2)-round(local!annualAmount/local!months)*(local!months-1)
)
),
/*creates transaction object*/
rule!CAS_createTransactionObject(
allocationTypeId: cons!CAS_TRANSACTION_TYPE_ID_ACCRUAL,
batchTypeId: cons!CAS_REFERENCE_DATA_ID_BATCH_TYPE_ONLINE,
amount: local!amount,
isAccrual: true,
transactionDate: local!expectedTransDate,
accountingDate: local!accountingDate,
transactionTimestamp: now(),
recordId: "20097314",
recordTypeId: cons!CAS_RECORD_TYPE_ID_POLICY,
policyId: "20097314",
transactionCurrency: local!currency
)
)
)
)

We are a little confused that when the policyEffectiveDate and expirationDate is less than 12 error is not encountered for Large segment