MTC-30 LTC issues

MTC-30 on latest firmware 1.6.9. Sending SMPTE conform 25fps signal to LTC in: I can see random dropouts on the timecode display while source is playing. Those dropouts can be heard as well on the LTC output. Not useable like this. In generel if playback is stopped and the LTC source remains sending the current frame as LTC, the MTC-30 stops seven frames beyond that TC position and the display for 'frames' is jumping around. It feels, like MTC-30 tries to interpret and filter something. It needs a mode in which the device simple and stupidly just shows and sends out whatever comes in. Right now not useable like that for LTC sources. I checked different older firmware. Behavior changes a little bit but no firmware version fixes anything.