Cannot fold DateTime UDF

[denis0x0D]

Predicate:

WHERE R.ts = DateTime::MakeDate(DateTime::Parse('%Y-%m-%d')("2023-10-20"));

Ast:

 (return '('('((FlatMap $3 (lambda '($4) (block '(
   (let $5 (ResourceType '"DateTime2.TM"))
   (let $6 (DataType 'String))
   (let $7 '($6 '"" '"1"))
   (let $8 (CallableType '('"1") '((CallableType '() '((OptionalType $5)) $7)) '($6) '((OptionalType (DataType 'Uint16)))))
   (let $9 (Udf '"DateTime2.Parse" (Void) (VoidType) '"" $8 (VoidType) '"" '())) 
   (return (OptionalIf (Coalesce (== (Member $4 '"ts") (FlatMap (Apply (Apply $9 (String '"%Y-%m-%d")) (String '"2023-10-20")) (lambda   '($10) (block '(
     (let $11 '($5 '"" '"1"))
     (let $12 (CallableType '() '((DataType 'Date)) $11))
     (let $13 (Udf '"DateTime2.MakeDate" (Void) (VoidType) '"" $12 (VoidType) '"" '('('"blocks") '('"strict"))))
     (return (Just (Apply $13 $10)))
   ))))) (Bool 'false)) $4))
 )))) '())) '()))
)