DSPS no transmission 00hex

Hi Dialog,
I'm evaulating the DSPS, connecting a OTP-programmend PAN1740 device with a PAN1740 modul as host in debug mode.
I'm able to transfer data in both directions but no 00hex. All other values from 01hex ... FFhex seem to be transmittable.
示例1:单一电报00十六进制(从PC-termial)PAN1740(Host) => PAN170(device) => no telegram to measure (Scope)
example 2: 2 telegram 01hex; 00hex (from PC-termial) PAN1740(Host) => PAN170(device) => 01hex-telgram (Scope)
example 3: 3 telegram 01hex; 00hex; 02hex (from PC-termial) PAN1740(Host) => PAN170(device) => 01hex-telgram (Scope)
example 4: 3 telgram 01hex; 02hex; 03hex (from PC-termial) PAN1740(Host) => PAN170(device) => 3 telgrams 01hex; 02hex; 03hex (Scope)
Is there any reason for that?
Thank you very much,
Peter

SDK: DA14580_DSPS_3.150.2___13_2_2015