CAN bus messages are received with long delay

Setup:

PCAN-Module with PCAN-View-SW sends 3 messages periodically with 100ms cycle time (IDs: 0x100, 0x150, 0x50B).
The message 0x100 is received and sent back directly via CAN-ID 0x777.

After the first start of the boards (nitrogen6x and nitrogen6x_max have the same behaviour) the answer is shown in PCAN-View with 0x777 partially with a delay of twice the cycle time. When you change a byte it takes even longer until the changed value is shown in PCAN-View. After a few seconds the delay has increased to 10 seconds.

The terminal shows this output

Starting remote application.
"FB_MULTI_BUFFER" "2"
"QML2_IMPORT_PATH" "/data/user/qt/qmlplugins"
"QT_GSTREAMER_CAMERABIN_VIDEOSRC" "mxc_v4l2=imxv4l2videosrc,v4l2src"
"QT_IM_MODULE" "qtvirtualkeyboard"
"QT_QPA_EGLFS_FORCEVSYNC" "1"
"QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS" "/dev/input/event0"
"QT_QUICK_CONTROLS_STYLE" "Flat"
"XDG_RUNTIME_DIR" "/tmp"
"/opt/CAN_Perf_Test_01/bin/CAN_Perf_Test_01" ()
QML debugging is enabled. Only use this in a safe environment.
Unable to query physical screen size, defaulting to 100 dpi.
To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).
"SocketCanBackend: No such configuration as 4 in SocketCanBackend"
Cannot apply parameter: QCanBusDevice::ConfigurationKey(BitRateKey) with value: QVariant(int, 1000000)

The least two lines look like an error message and have always been there. But until now the CAN-Bus has worked correctly.
Before is was possible to workaround this problem by disabling the QML UI but this does not work anymore and the problem persists.