IllegalArgumentException:Unsupported operator = by using regex in JSONPath Count Match

Hello all,

I am trying to create a test case with assertion based on JSONPath Count Match and regex. But I get always the error message from SoapUI:

Assertion failed for path [$.flightOfferList.flightOffer[*].connectionList.connection[*].segmentList.segment[?(@.departureDateTime =~ /2018-08-15T17:10:00/)]] : IllegalArgumentException:Unsupported operator =

If I put the message to check on http://jsonpath.herokuapp.com/ and use the same JSON Path then it works without problems.

Is there a bug in SoapUI? (I'm using the version 5.4.0 on Windows). Or is my JSONPath expression wrong?

Here is my JSON message, that I'm trying to check:

{"flightOfferList": {"flightOffer": [
      {
      "salePrice": 312235,
      "salesPriceCurrency": "EUR",
      "onlyWithHotel": false,
      "ticketTimeLimit": "2018-06-11",
      "bookingInOptionUntil": "1111-11-11",
      "sypoCode": "MERC",
      "agfaCode": "IFBP",
      "luggageIncluded": true,
      "status": "VKE",
      "connectionList": {"connection": [      {
         "departure": "FRA",
         "destination": "JFK",
         "flightDate": "2018-08-15",
         "serviceClass": "Y",
         "touristicDepartureDate": "2018-08-15",
         "touristicArrivalDate": "2018-08-15",
         "numberOfFlightNights": 0,
         "segmentList": {"segment": [         {
            "departure": "FRA",
            "destination": "JFK",
            "departureDateTime": "2018-08-15T17:10:00",
            "arrivalDateTime": "2018-08-15T19:55:00",
            "carrierCodeMkt": "UA",
            "carrierCodeOp": "LH",
            "bookingClass": "Y ",
            "flightNumber": "8843",
            "overnight": false,
            "nonStop": true,
            "seatReservationPossible": false
         }]}
      }]}
   },
      {
      "salePrice": 313835,
      "salesPriceCurrency": "EUR",
      "onlyWithHotel": false,
      "ticketTimeLimit": "2018-06-11",
      "bookingInOptionUntil": "1111-11-11",
      "sypoCode": "MERC",
      "agfaCode": "IFBP",
      "luggageIncluded": true,
      "status": "VKE",
      "connectionList": {"connection": [      {
         "departure": "FRA",
         "destination": "JFK",
         "flightDate": "2018-08-15",
         "serviceClass": "Y",
         "touristicDepartureDate": "2018-08-15",
         "touristicArrivalDate": "2018-08-15",
         "numberOfFlightNights": 0,
         "segmentList": {"segment": [         {
            "departure": "FRA",
            "destination": "JFK",
            "departureDateTime": "2018-08-15T16:00:00",
            "arrivalDateTime": "2018-08-15T20:00:00",
            "carrierCodeMkt": "LH",
            "carrierCodeOp": "LH",
            "bookingClass": "Y ",
            "flightNumber": "4838",
            "overnight": false,
            "nonStop": true,
            "seatReservationPossible": false
         }]}
      }]}
   },
      {
      "salePrice": 313835,
      "salesPriceCurrency": "EUR",
      "onlyWithHotel": false,
      "ticketTimeLimit": "2018-06-11",
      "bookingInOptionUntil": "1111-11-11",
      "sypoCode": "MERC",
      "agfaCode": "IFBP",
      "luggageIncluded": true,
      "status": "VKE",
      "connectionList": {"connection": [      {
         "departure": "FRA",
         "destination": "JFK",
         "flightDate": "2018-08-15",
         "serviceClass": "Y",
         "touristicDepartureDate": "2018-08-15",
         "touristicArrivalDate": "2018-08-15",
         "numberOfFlightNights": 0,
         "segmentList": {"segment": [         {
            "departure": "FRA",
            "destination": "JFK",
            "departureDateTime": "2018-08-15T16:00:00",
            "arrivalDateTime": "2018-08-15T20:00:00",
            "carrierCodeMkt": "LH",
            "carrierCodeOp": "LH",
            "bookingClass": "Y ",
            "flightNumber": "4839",
            "overnight": false,
            "nonStop": true,
            "seatReservationPossible": false
         }]}
      }]}
   },
      {
      "salePrice": 313835,
      "salesPriceCurrency": "EUR",
      "onlyWithHotel": false,
      "ticketTimeLimit": "2018-06-11",
      "bookingInOptionUntil": "1111-11-11",
      "sypoCode": "MERC",
      "agfaCode": "IFBP",
      "luggageIncluded": true,
      "status": "VKE",
      "connectionList": {"connection": [      {
         "departure": "FRA",
         "destination": "JFK",
         "flightDate": "2018-08-15",
         "serviceClass": "Y",
         "touristicDepartureDate": "2018-08-15",
         "touristicArrivalDate": "2018-08-15",
         "numberOfFlightNights": 0,
         "segmentList": {"segment": [         {
            "departure": "FRA",
            "destination": "JFK",
            "departureDateTime": "2018-08-15T17:10:00",
            "arrivalDateTime": "2018-08-15T19:55:00",
            "carrierCodeMkt": "LH",
            "carrierCodeOp": "LH",
            "bookingClass": "Y ",
            "flightNumber": "404",
            "overnight": false,
            "nonStop": true,
            "seatReservationPossible": false
         }]}
      }]}
   }
]}}

And my JSON Path, that I would like to use is

$.flightOfferList.flightOffer[*].connectionList.connection[*].segmentList.segment[?(@.departureDateTime  =~ /2018-08-15T17:10:00/)]

Thanks for any hints!